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points</title> <meta name="description" content="Search results for: bubble points"> <meta name="keywords" content="bubble points"> <meta name="viewport" content="width=device-width, initial-scale=1, minimum-scale=1, maximum-scale=1, user-scalable=no"> <meta charset="utf-8"> <link href="https://cdn.waset.org/favicon.ico" type="image/x-icon" rel="shortcut icon"> <link href="https://cdn.waset.org/static/plugins/bootstrap-4.2.1/css/bootstrap.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/plugins/fontawesome/css/all.min.css" rel="stylesheet"> <link href="https://cdn.waset.org/static/css/site.css?v=150220211555" rel="stylesheet"> </head> <body> <header> <div class="container"> <nav class="navbar navbar-expand-lg navbar-light"> <a class="navbar-brand" href="https://waset.org"> <img src="https://cdn.waset.org/static/images/wasetc.png" alt="Open Science Research Excellence" title="Open Science Research Excellence" /> </a> <button class="d-block d-lg-none navbar-toggler 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id="custom-search-input"> <div class="input-group"> <i class="fas fa-search"></i> <input type="text" class="search-query" name="q" placeholder="Author, Title, Abstract, Keywords" value="bubble points"> <input type="submit" class="btn_search" value="Search"> </div> </div> </form> </div> </div> <div class="row mt-3"> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Commenced</strong> in January 2007</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Frequency:</strong> Monthly</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Edition:</strong> International</div> </div> </div> <div class="col-sm-3"> <div class="card"> <div class="card-body"><strong>Paper Count:</strong> 2586</div> </div> </div> </div> <h1 class="mt-3 mb-3 text-center" style="font-size:1.6rem;">Search results for: bubble points</h1> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2586</span> Bubble Growth in a Two Phase Upward Flow in a Miniature Tube</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=R.%20S.%20Hassani">R. S. Hassani</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20Chikh"> S. Chikh</a>, <a href="https://publications.waset.org/abstracts/search?q=L.%20Tadrist"> L. Tadrist</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20Radev"> S. Radev</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A bubbly flow in a vertical miniature tube is analyzed theoretically. The liquid and gas phase are co-current flowing upward. The gas phase is injected via a nozzle whose inner diameter is 0.11mm and it is placed on the axis of the tube. A force balance is applied on the bubble at its detachment. The set of governing equations are solved by use of Mathematica software. The bubble diameter and the bubble generation frequency are determined for various inlet phase velocities represented by the inlet mass quality. The results show different behavior of bubble growth and detachment depending on the tube size. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=two%20phase%20flow" title="two phase flow">two phase flow</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20growth" title=" bubble growth"> bubble growth</a>, <a href="https://publications.waset.org/abstracts/search?q=mini-channel" title=" mini-channel"> mini-channel</a>, <a href="https://publications.waset.org/abstracts/search?q=generation%20frequency" title=" generation frequency"> generation frequency</a> </p> <a href="https://publications.waset.org/abstracts/7322/bubble-growth-in-a-two-phase-upward-flow-in-a-miniature-tube" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/7322.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">432</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2585</span> Investigation of Bubble Growth During Nucleate Boiling Using CFD</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=K.%20Jagannath">K. Jagannath</a>, <a href="https://publications.waset.org/abstracts/search?q=Akhilesh%20Kotian"> Akhilesh Kotian</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20S.%20Sharma"> S. S. Sharma</a>, <a href="https://publications.waset.org/abstracts/search?q=Achutha%20Kini%20U."> Achutha Kini U.</a>, <a href="https://publications.waset.org/abstracts/search?q=P.%20R.%20Prabhu"> P. R. Prabhu </a> </p> <p class="card-text"><strong>Abstract:</strong></p> Boiling process is characterized by the rapid formation of vapour bubbles at the solid–liquid interface (nucleate boiling) with pre-existing vapour or gas pockets. Computational fluid dynamics (CFD) is an important tool to study bubble dynamics. In the present study, CFD simulation has been carried out to determine the bubble detachment diameter and its terminal velocity. Volume of fluid method is used to model the bubble and the surrounding by solving single set of momentum equations and tracking the volume fraction of each of the fluids throughout the domain. In the simulation, bubble is generated by allowing water-vapour to enter a cylinder filled with liquid water through an inlet at the bottom. After the bubble is fully formed, the bubble detaches from the surface and rises up during which the bubble accelerates due to the net balance between buoyancy force and viscous drag. Finally when these forces exactly balance each other, it attains a constant terminal velocity. The bubble detachment diameter and the terminal velocity of the bubble are captured by the monitor function provided in FLUENT. The detachment diameter and the terminal velocity obtained is compared with the established results based on the shape of the bubble. A good agreement is obtained between the results obtained from simulation and the equations in comparison with the established results. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubble%20growth" title="bubble growth">bubble growth</a>, <a href="https://publications.waset.org/abstracts/search?q=computational%20fluid%20dynamics" title=" computational fluid dynamics"> computational fluid dynamics</a>, <a href="https://publications.waset.org/abstracts/search?q=detachment%20diameter" title=" detachment diameter"> detachment diameter</a>, <a href="https://publications.waset.org/abstracts/search?q=terminal%20velocity" title=" terminal velocity"> terminal velocity</a> </p> <a href="https://publications.waset.org/abstracts/26289/investigation-of-bubble-growth-during-nucleate-boiling-using-cfd" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/26289.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">386</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2584</span> CFD Simulation and Experimental Validation of the Bubble-Induced Flow during Electrochemical Water Splitting</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Gabriel%20Wosiak">Gabriel Wosiak</a>, <a href="https://publications.waset.org/abstracts/search?q=Jeyse%20da%20Silva"> Jeyse da Silva</a>, <a href="https://publications.waset.org/abstracts/search?q=Sthefany%20S.%20Sena"> Sthefany S. Sena</a>, <a href="https://publications.waset.org/abstracts/search?q=Renato%20N.%20de%20Andrade"> Renato N. de Andrade</a>, <a href="https://publications.waset.org/abstracts/search?q=Ernesto%20Pereira"> Ernesto Pereira</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The bubble formation during hydrogen production by electrolysis and several electrochemical processes is an inherent phenomenon and can impact the energy consumption of the processes. In this work, it was reported both experimental and computational results describe the effect of bubble displacement, which, under the cases investigated, leads to the formation of a convective flow in the solution. The process is self-sustained, and a solution vortex is formed, which modifies the bubble growth and covering at the electrode surface. Using the experimental data, we have built a model to simulate it, which, with high accuracy, describes the phenomena. Then, it simulated many different experimental conditions and evaluated the effects of the boundary conditions on the bubble surface covering the surface. We have observed a position-dependent bubble covering the surface, which has an effect on the water-splitting efficiency. It was shown that the bubble covering is not uniform at the electrode surface, and using statistical analysis; it was possible to evaluate the influence of the gas type (H2 and O2), current density, and the bubble size (and cross-effects) on the covering fraction and the asymmetric behavior over the electrode surface. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=water%20splitting" title="water splitting">water splitting</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble" title=" bubble"> bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=electrolysis" title=" electrolysis"> electrolysis</a>, <a href="https://publications.waset.org/abstracts/search?q=hydrogen%20production" title=" hydrogen production"> hydrogen production</a> </p> <a href="https://publications.waset.org/abstracts/151356/cfd-simulation-and-experimental-validation-of-the-bubble-induced-flow-during-electrochemical-water-splitting" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/151356.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">100</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2583</span> 3D Microbubble Dynamics in a Weakly Viscous Fluid Near a Rigid Boundary Subject to Ultrasound</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=K.%20Manmi">K. Manmi</a>, <a href="https://publications.waset.org/abstracts/search?q=Q.%20X.%20Wang"> Q. X. Wang</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper investigates microbubble dynamics subject to ultrasound in a weakly viscous fluid near a rigid boundary. The phenomenon is simulated using a boundary integral method. The weak viscous effects are incorporated into the model through the normal stress balance across the bubble surface. The model agrees well with the Rayleigh-Plesset equation for a spherical bubble for several cycles. The effects of the fluid viscosity in the bubble dynamics are analyzed, including jet development, centroid movement and bubble volume. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=microbubble%20dynamics" title="microbubble dynamics">microbubble dynamics</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20jetting" title=" bubble jetting"> bubble jetting</a>, <a href="https://publications.waset.org/abstracts/search?q=viscous%20effect" title=" viscous effect"> viscous effect</a>, <a href="https://publications.waset.org/abstracts/search?q=boundary%20integral%20method" title=" boundary integral method"> boundary integral method</a> </p> <a href="https://publications.waset.org/abstracts/12981/3d-microbubble-dynamics-in-a-weakly-viscous-fluid-near-a-rigid-boundary-subject-to-ultrasound" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/12981.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">483</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2582</span> Analysis of Two Phase Hydrodynamics in a Column Flotation by Particle Image Velocimetry</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Balraju%20Vadlakonda">Balraju Vadlakonda</a>, <a href="https://publications.waset.org/abstracts/search?q=Narasimha%20Mangadoddy"> Narasimha Mangadoddy</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The hydrodynamic behavior in a laboratory column flotation was analyzed using particle image velocimetry. For complete characterization of column flotation, it is necessary to determine the flow velocity induced by bubbles in the liquid phase, the bubble velocity and bubble characteristics:diameter,shape and bubble size distribution. An experimental procedure for analyzing simultaneous, phase-separated velocity measurements in two-phase flows was introduced. The non-invasive PIV technique has used to quantify the instantaneous flow field, as well as the time averaged flow patterns in selected planes of the column. Using the novel particle velocimetry (PIV) technique by the combination of fluorescent tracer particles, shadowgraphy and digital phase separation with masking technique measured the bubble velocity as well as the Reynolds stresses in the column. Axial and radial mean velocities as well as fluctuating components were determined for both phases by averaging the sufficient number of double images. Bubble size distribution was cross validated with high speed video camera. Average turbulent kinetic energy of bubble were analyzed. Different air flow rates were considered in the experiments. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=particle%20image%20velocimetry%20%28PIV%29" title="particle image velocimetry (PIV)">particle image velocimetry (PIV)</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20velocity" title=" bubble velocity"> bubble velocity</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20diameter" title=" bubble diameter"> bubble diameter</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulent%20kinetic%20energy" title=" turbulent kinetic energy"> turbulent kinetic energy</a> </p> <a href="https://publications.waset.org/abstracts/11962/analysis-of-two-phase-hydrodynamics-in-a-column-flotation-by-particle-image-velocimetry" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/11962.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">510</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2581</span> Simulations of Cryogenic Cavitation of Low Temperature Fluids with Thermodynamics Effects</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=A.%20Alhelfi">A. Alhelfi</a>, <a href="https://publications.waset.org/abstracts/search?q=B.%20Sunden"> B. Sunden</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Cavitation in cryogenic liquids is widely present in contemporary science. In the current study, we re-examine a previously validated acoustic cavitation model which was developed for a gas bubble in liquid water. Furthermore, simulations of cryogenic fluids including the thermal effect, the effect of acoustic pressure amplitude and the frequency of sound field on the bubble dynamics are presented. A gas bubble (Helium) in liquids Nitrogen, Oxygen and Hydrogen in an acoustic field at ambient pressure and low temperature is investigated numerically. The results reveal that the oscillation of the bubble in liquid Hydrogen fluctuates more than in liquids Oxygen and Nitrogen. The oscillation of the bubble in liquids Oxygen and Nitrogen is approximately similar. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=cryogenic%20liquids" title="cryogenic liquids">cryogenic liquids</a>, <a href="https://publications.waset.org/abstracts/search?q=cavitation" title=" cavitation"> cavitation</a>, <a href="https://publications.waset.org/abstracts/search?q=rocket%20engineering" title=" rocket engineering"> rocket engineering</a>, <a href="https://publications.waset.org/abstracts/search?q=ultrasound" title=" ultrasound"> ultrasound</a> </p> <a href="https://publications.waset.org/abstracts/20592/simulations-of-cryogenic-cavitation-of-low-temperature-fluids-with-thermodynamics-effects" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/20592.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">322</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2580</span> Design and Fabrication of Micro-Bubble Oxygenator</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Chiang-Ho%20Cheng">Chiang-Ho Cheng</a>, <a href="https://publications.waset.org/abstracts/search?q=An-Shik%20Yang"> An-Shik Yang</a>, <a href="https://publications.waset.org/abstracts/search?q=Hong-Yih%20Cheng"> Hong-Yih Cheng</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This paper applies the MEMS technology to design and fabricate a micro-bubble generator by a piezoelectric actuator. Coupled with a nickel nozzle plate, an annular piezoelectric ceramic was utilized as the primary structure of the generator. In operations, the piezoelectric element deforms transversely under an electric field applied across the thickness of the generator. The surface of the nozzle plate can expand or contract because of the induction of radial strain, resulting in the whole structure to bend, and successively transport oxygen micro-bubbles into the blood flow for enhancing the oxygen content in blood. In the tests, a high magnification microscope and a high speed CCD camera were employed to photograph the time evolution of meniscus shape of gaseous bubbles dispensed from the micro-bubble generator for flow visualization. This investigation thus explored the bubble formation process including the influences of inlet gas pressure along with driving voltage and resonance frequency on the formed bubble extent. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=micro-bubble" title="micro-bubble">micro-bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=oxygenator" title=" oxygenator"> oxygenator</a>, <a href="https://publications.waset.org/abstracts/search?q=nozzle" title=" nozzle"> nozzle</a>, <a href="https://publications.waset.org/abstracts/search?q=piezoelectric" title=" piezoelectric"> piezoelectric</a> </p> <a href="https://publications.waset.org/abstracts/67526/design-and-fabrication-of-micro-bubble-oxygenator" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/67526.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">319</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2579</span> CFD Modeling of Boiling in a Microchannel Based On Phase-Field Method</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Rahim%20Jafari">Rahim Jafari</a>, <a href="https://publications.waset.org/abstracts/search?q=Tuba%20Okutucu-%C3%96zyurt"> Tuba Okutucu-Özyurt</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The hydrodynamics and heat transfer characteristics of a vaporized elongated bubble in a rectangular microchannel have been simulated based on Cahn-Hilliard phase-field method. In the simulations, the initially nucleated bubble starts growing as it comes in contact with superheated water. The growing shape of the bubble compared with the available experimental data in the literature. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=microchannel" title="microchannel">microchannel</a>, <a href="https://publications.waset.org/abstracts/search?q=boiling" title=" boiling"> boiling</a>, <a href="https://publications.waset.org/abstracts/search?q=Cahn-Hilliard%20method" title=" Cahn-Hilliard method"> Cahn-Hilliard method</a>, <a href="https://publications.waset.org/abstracts/search?q=simulation" title=" simulation"> simulation</a> </p> <a href="https://publications.waset.org/abstracts/18878/cfd-modeling-of-boiling-in-a-microchannel-based-on-phase-field-method" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/18878.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">424</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2578</span> Prediction of Bubbly Plume Characteristics Using the Self-Similarity Model</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Li%20Chen">Li Chen</a>, <a href="https://publications.waset.org/abstracts/search?q=Alex%20Skvortsov"> Alex Skvortsov</a>, <a href="https://publications.waset.org/abstracts/search?q=Chris%20Norwood"> Chris Norwood</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Gas releasing into water can be found in for many industrial situations. This process results in the formation of bubbles and acoustic emission which depends upon the bubble characteristics. If the bubble creation rates (bubble volume flow rate) are of interest, an inverse method has to be used based on the measurement of acoustic emission. However, there will be sound attenuation through the bubbly plume which will influence the measurement and should be taken into consideration in the model. The sound transmission through the bubbly plume depends on the characteristics of the bubbly plume, such as the shape and the bubble distributions. In this study, the bubbly plume shape is modelled using a self-similarity model, which has been normally applied for a single phase buoyant plume. The prediction is compared with the experimental data. It has been found the model can be applied to a buoyant plume of gas-liquid mixture. The influence of the gas flow rate and discharge nozzle size is studied. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubbly%20plume" title="bubbly plume">bubbly plume</a>, <a href="https://publications.waset.org/abstracts/search?q=buoyant%20plume" title=" buoyant plume"> buoyant plume</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20acoustics" title=" bubble acoustics"> bubble acoustics</a>, <a href="https://publications.waset.org/abstracts/search?q=self-similarity%20model" title=" self-similarity model"> self-similarity model</a> </p> <a href="https://publications.waset.org/abstracts/65469/prediction-of-bubbly-plume-characteristics-using-the-self-similarity-model" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/65469.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">287</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2577</span> Effect of Knowledge of Bubble Point Pressure on Estimating PVT Properties from Correlations</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Ahmed%20El-Banbi">Ahmed El-Banbi</a>, <a href="https://publications.waset.org/abstracts/search?q=Ahmed%20El-Maraghi"> Ahmed El-Maraghi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> PVT properties are needed as input data in all reservoir, production, and surface facilities engineering calculations. In the absence of PVT reports on valid reservoir fluid samples, engineers rely on PVT correlations to generate the required PVT data. The accuracy of PVT correlations varies, and no correlation group has been found to provide accurate results for all oil types. The effect of inaccurate PVT data can be significant in engineering calculations and is well documented in the literature. Bubble point pressure can sometimes be obtained from external sources. In this paper, we show how to utilize the known bubble point pressure to improve the accuracy of calculated PVT properties from correlations. We conducted a systematic study using around 250 reservoir oil samples to quantify the effect of pre-knowledge of bubble point pressure. The samples spanned a wide range of oils, from very volatile oils to black oils and all the way to low-GOR oils. A method for shifting both undersaturated and saturated sections of the PVT properties curves to the correct bubble point is explained. Seven PVT correlation families were used in this study. All PVT properties (e.g., solution gas-oil ratio, formation volume factor, density, viscosity, and compressibility) were calculated using the correct bubble point pressure and the correlation estimated bubble point pressure. Comparisons between the calculated PVT properties and actual laboratory-measured values were made. It was found that pre-knowledge of bubble point pressure and using the shifting technique presented in the paper improved the correlation-estimated values by 10% to more than 30%. The most improvement was seen in the solution gas-oil ratio and formation volume factor. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=PVT%20data" title="PVT data">PVT data</a>, <a href="https://publications.waset.org/abstracts/search?q=PVT%20properties" title=" PVT properties"> PVT properties</a>, <a href="https://publications.waset.org/abstracts/search?q=PVT%20correlations" title=" PVT correlations"> PVT correlations</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20point%20pressure" title=" bubble point pressure"> bubble point pressure</a> </p> <a href="https://publications.waset.org/abstracts/174002/effect-of-knowledge-of-bubble-point-pressure-on-estimating-pvt-properties-from-correlations" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/174002.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">63</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2576</span> Identification of the Main Transition Velocities in a Bubble Column Based on a Modified Shannon Entropy</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Stoyan%20Nedeltchev">Stoyan Nedeltchev</a>, <a href="https://publications.waset.org/abstracts/search?q=Markus%20Schubert"> Markus Schubert</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The gas holdup fluctuations in a bubble column (0.15 m in ID) have been recorded by means of a conductivity wire-mesh sensor in order to extract information about the main transition velocities. These parameters are very important for bubble column design, operation and scale-up. For this purpose, the classical definition of the Shannon entropy was modified and used to identify both the onset (at UG=0.034 m/s) of the transition flow regime and the beginning (at UG=0.089 m/s) of the churn-turbulent flow regime. The results were compared with the Kolmogorov entropy (KE) results. A slight discrepancy was found, namely the transition velocities identified by means of the KE were shifted to somewhat higher (0.045 and 0.101 m/s) superficial gas velocities UG. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubble%20column" title="bubble column">bubble column</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20holdup%20fluctuations" title=" gas holdup fluctuations"> gas holdup fluctuations</a>, <a href="https://publications.waset.org/abstracts/search?q=modified%20Shannon%20entropy" title=" modified Shannon entropy"> modified Shannon entropy</a>, <a href="https://publications.waset.org/abstracts/search?q=Kolmogorov%20entropy" title=" Kolmogorov entropy"> Kolmogorov entropy</a> </p> <a href="https://publications.waset.org/abstracts/42948/identification-of-the-main-transition-velocities-in-a-bubble-column-based-on-a-modified-shannon-entropy" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/42948.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">328</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2575</span> Entropy Analysis in a Bubble Column Based on Ultrafast X-Ray Tomography Data</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Stoyan%20Nedeltchev">Stoyan Nedeltchev</a>, <a href="https://publications.waset.org/abstracts/search?q=Markus%20Schubert"> Markus Schubert</a> </p> <p class="card-text"><strong>Abstract:</strong></p> By means of the ultrafast X-ray tomography facility, data were obtained at different superficial gas velocities <em>U</em><sub>G</sub> in a bubble column (0.1 m in ID) operated with an air-deionized water system at ambient conditions. Raw reconstructed images were treated by both the information entropy (IE) and the reconstruction entropy (RE) algorithms in order to identify the main transition velocities in a bubble column. The IE values exhibited two well-pronounced minima at <em>U</em><sub>G</sub>=0.025 m/s and <em>U</em><sub>G</sub>=0.085 m/s identifying the boundaries of the homogeneous, transition and heterogeneous regimes. The RE extracted from the central region of the column’s cross-section exhibited only one characteristic peak at <em>U</em><sub>G</sub>=0.03 m/s, which was attributed to the transition from the homogeneous to the heterogeneous flow regime. This result implies that the transition regime is non-existent in the core of the column. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubble%20column" title="bubble column">bubble column</a>, <a href="https://publications.waset.org/abstracts/search?q=ultrafast%20X-ray%20tomography" title=" ultrafast X-ray tomography"> ultrafast X-ray tomography</a>, <a href="https://publications.waset.org/abstracts/search?q=information%20entropy" title=" information entropy"> information entropy</a>, <a href="https://publications.waset.org/abstracts/search?q=reconstruction%20entropy" title=" reconstruction entropy"> reconstruction entropy</a> </p> <a href="https://publications.waset.org/abstracts/43128/entropy-analysis-in-a-bubble-column-based-on-ultrafast-x-ray-tomography-data" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/43128.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">391</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2574</span> Electric Field Effect on the Rise of Single Bubbles during Boiling</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=N.%20Masoudnia">N. Masoudnia</a>, <a href="https://publications.waset.org/abstracts/search?q=M.%20Fatahi"> M. Fatahi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> An experimental study of saturated pool boiling on a single artificial nucleation site without and with the application of an electric field on the boiling surface has been conducted. N-pentane is boiling on a copper surface and is recorded with a high speed camera providing high quality pictures and movies. The accuracy of the visualization allowed establishing an experimental bubble growth law from a large number of experiments. This law shows that the evaporation rate is decreasing during the bubble growth, and underlines the importance of liquid motion induced by the preceding bubble. Bubble rise is therefore studied: once detached, bubbles accelerate vertically until reaching a maximum velocity in good agreement with a correlation from literature. The bubbles then turn to another direction. The effect of applying an electric field on the boiling surface in finally studied. In addition to changes of the bubble shape, changes are also shown in the liquid plume and the convective structures above the surface. Lower maximum rising velocities were measured in the presence of electric fields, especially with a negative polarity. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=single%20bubbles" title="single bubbles">single bubbles</a>, <a href="https://publications.waset.org/abstracts/search?q=electric%20field" title=" electric field"> electric field</a>, <a href="https://publications.waset.org/abstracts/search?q=boiling" title=" boiling"> boiling</a>, <a href="https://publications.waset.org/abstracts/search?q=effect" title=" effect "> effect </a> </p> <a href="https://publications.waset.org/abstracts/50072/electric-field-effect-on-the-rise-of-single-bubbles-during-boiling" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/50072.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">270</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2573</span> Measurement of Steady Streaming from an Oscillating Bubble Using Particle Image Velocimetry</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Yongseok%20Kwon">Yongseok Kwon</a>, <a href="https://publications.waset.org/abstracts/search?q=Woowon%20Jeong"> Woowon Jeong</a>, <a href="https://publications.waset.org/abstracts/search?q=Eunjin%20Cho"> Eunjin Cho</a>, <a href="https://publications.waset.org/abstracts/search?q=Sangkug%20Chung"> Sangkug Chung</a>, <a href="https://publications.waset.org/abstracts/search?q=Kyehan%20Rhee"> Kyehan Rhee</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Steady streaming flow fields induced by a 500 um bubble oscillating at 12 kHz were measured using microscopic particle image velocimetry (PIV). The accuracy of velocity measurement using a micro PIV system was checked by comparing the measured velocity fields with the theoretical velocity profiles in fully developed laminar flow. The steady streaming flow velocities were measured in the saggital plane of the bubble attached on the wall. Measured velocity fields showed upward jet flow with two symmetric counter-rotating vortices, and the maximum streaming velocity was about 12 mm/s, which was within the velocity ranges measured by other researchers. The measured streamlines were compared with the analytic solution, and they also showed a reasonable agreement. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=oscillating%20bubble" title="oscillating bubble">oscillating bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=particle%20image%20velocimetry" title=" particle image velocimetry"> particle image velocimetry</a>, <a href="https://publications.waset.org/abstracts/search?q=microstreaming" title=" microstreaming"> microstreaming</a>, <a href="https://publications.waset.org/abstracts/search?q=vortices" title=" vortices"> vortices</a>, <a href="https://publications.waset.org/abstracts/search?q=" title=" "> </a> </p> <a href="https://publications.waset.org/abstracts/1749/measurement-of-steady-streaming-from-an-oscillating-bubble-using-particle-image-velocimetry" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/1749.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">413</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2572</span> Efficient Oxygen Evolution and Gas Bubble Release by a Low-Bubble-Adhesion Iron-Nickel Vanadate Electrocatalyst</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Kamran%20Dastafkan">Kamran Dastafkan</a>, <a href="https://publications.waset.org/abstracts/search?q=Chuan%20Zhao"> Chuan Zhao</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Improving surface chemistry is a promising approach in addition to the rational alteration in the catalyst composition to advance water electrolysis. Here, we demonstrate an evident enhancement of oxygen evolution on an iron-nickel vanadate catalyst synthesized by a facile successive ionic adsorption and reaction method. The vanadate-modified catalyst demonstrates a highly efficient oxygen evolution in 1 M KOH by requiring low overpotentials of 274 and 310 mV for delivering large current densities of 100 and 400 mA cm⁻², respectively where vigorous gas bubble evolution occurs. Vanadate modification augments the OER activity from three aspects. (i) Both the electrochemical surface area (47.1 cm²) and intrinsic activity (318 mV to deliver 10 mA cm⁻² per unit ECSA) of the catalytic sites are improved. (ii) The amorphous and roughened nanoparticle-comprised catalyst film exhibits a high surface wettability and a low-gas bubble-adhesion, which is beneficial for the accelerated mass transport and gas bubble dissipation at large current densities. The gas bubble dissipation behavior is studied by operando dynamic specific resistance measurements where a significant change in the variation of the interfacial resistance during the OER is detected for the vanadate-modified catalyst. (iii) The introduced vanadate poly-oxo-anions with high charge density have electronic interplay with Fe and Ni catalytic centers. Raman study reveals the structural evolution of β-NiOOH and γ-FeOOH phases during the OER through the vanadate-active site synergistic interactions. Achievement of a high catalytic turnover of 0.12 s⁻¹ put the developed FeNi vanadate among the best recent catalysts for water oxidation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=gas%20bubble%20dissipation" title="gas bubble dissipation">gas bubble dissipation</a>, <a href="https://publications.waset.org/abstracts/search?q=iron-nickel%20vanadate" title=" iron-nickel vanadate"> iron-nickel vanadate</a>, <a href="https://publications.waset.org/abstracts/search?q=low-gas%20bubble-adhesion%20catalyst" title=" low-gas bubble-adhesion catalyst"> low-gas bubble-adhesion catalyst</a>, <a href="https://publications.waset.org/abstracts/search?q=oxygen%20evolution%20reaction" title=" oxygen evolution reaction"> oxygen evolution reaction</a> </p> <a href="https://publications.waset.org/abstracts/118358/efficient-oxygen-evolution-and-gas-bubble-release-by-a-low-bubble-adhesion-iron-nickel-vanadate-electrocatalyst" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/118358.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">131</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2571</span> Removal of Copper from Wastewaters by Nano-Micro Bubble Ion Flotation</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=R.%20Ahmadi">R. Ahmadi</a>, <a href="https://publications.waset.org/abstracts/search?q=A.%20Khodadadi"> A. Khodadadi</a>, <a href="https://publications.waset.org/abstracts/search?q=M.%20Abdollahi"> M. Abdollahi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The removal of copper from a dilute synthetic wastewater (10 mg/L) was studied by ion flotation at laboratory scale. Anionic sodium dodecyl sulfate (SDS) was used as a collector and ethanol as a frother. Different parameters such as pH, collector and frother concentrations, foam height and bubble size distribution (multi bubble ion flotation) were tested to determine the optimum flotation conditions in a Denver type flotation machine. To see into the effect of bubbles size distribution in this paper, a nano-micro bubble generator was designed. The nano and microbubbles that are generated in this way were combined with normal size bubbles generated mechanically. Under the optimum conditions (concentration of SDS: 192mg/l, ethanol: 0.5%v/v, pH value: 4 and froth height=12.5 cm) the best removal obtained for the system Cu/SDS with a dry foam (water recovery: 15.5%) was 85.6%. Coalescence of nano-microbubbles with bubbles of normal size belonging to mechanical flotation cell improved the removal of Cu to a maximum floatability of 92.8% and reduced the water recovery to a 13.1%.The flotation time decreased considerably at 37.5% when the multi bubble ion flotation was used. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=froth%20flotation" title="froth flotation">froth flotation</a>, <a href="https://publications.waset.org/abstracts/search?q=copper" title=" copper"> copper</a>, <a href="https://publications.waset.org/abstracts/search?q=water%20treatment" title=" water treatment"> water treatment</a>, <a href="https://publications.waset.org/abstracts/search?q=optimization" title=" optimization"> optimization</a>, <a href="https://publications.waset.org/abstracts/search?q=recycling" title=" recycling"> recycling</a> </p> <a href="https://publications.waset.org/abstracts/1665/removal-of-copper-from-wastewaters-by-nano-micro-bubble-ion-flotation" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/1665.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">502</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2570</span> Rising of Single and Double Bubbles during Boiling and Effect of Electric Field in This Process</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Masoud%20Gholam%20Ale%20Mohammad">Masoud Gholam Ale Mohammad</a>, <a href="https://publications.waset.org/abstracts/search?q=Mojtaba%20Hafezi%20Birgani"> Mojtaba Hafezi Birgani</a> </p> <p class="card-text"><strong>Abstract:</strong></p> An experimental study of saturated pool boiling on a single artificial nucleation site without and with the application of an electric field on the boiling surface has been conducted. N-pentane is boiling on a copper surface and is recorded with a high speed camera providing high quality pictures and movies. The accuracy of the visualization allowed establishing an experimental bubble growth law from a large number of experiments. This law shows that the evaporation rate is decreasing during the bubble growth, and underlines the importance of liquid motion induced by the preceding bubble. Bubble rise is therefore studied: once detached, bubbles accelerate vertically until reaching a maximum velocity in good agreement with a correlation from literature. The bubbles then turn to another direction. The effect of applying an electric field on the boiling surface in finally studied. In addition to changes in the bubble shape, changes are also shown in the liquid plume and the convective structures above the surface. Lower maximum rising velocities were measured in the presence of electric fields, especially with a negative polarity. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=single%20and%20double%20bubbles" title="single and double bubbles">single and double bubbles</a>, <a href="https://publications.waset.org/abstracts/search?q=electric%20field" title=" electric field"> electric field</a>, <a href="https://publications.waset.org/abstracts/search?q=boiling" title=" boiling"> boiling</a>, <a href="https://publications.waset.org/abstracts/search?q=rising" title=" rising"> rising</a> </p> <a href="https://publications.waset.org/abstracts/87592/rising-of-single-and-double-bubbles-during-boiling-and-effect-of-electric-field-in-this-process" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/87592.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">226</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2569</span> Liquid Temperature Effect on Sound Propagation in Polymeric Solution with Gas Bubbles</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=S.%20Levitsky">S. Levitsky </a> </p> <p class="card-text"><strong>Abstract:</strong></p> Acoustic properties of polymeric liquids are high sensitive to free gas traces in the form of fine bubbles. Their presence is typical for such liquids because of chemical reactions, small wettability of solid boundaries, trapping of air in technological operations, etc. Liquid temperature influences essentially its rheological properties, which may have an impact on the bubble pulsations and sound propagation in the system. The target of the paper is modeling of the liquid temperature effect on single bubble dynamics and sound dispersion and attenuation in polymeric solution with spherical gas bubbles. The basic sources of attenuation (heat exchange between gas in microbubbles and surrounding liquid, rheological and acoustic losses) are taken into account. It is supposed that in the studied temperature range the interface mass transfer has a minor effect on bubble dynamics. The results of the study indicate that temperature raise yields enhancement of bubble pulsations and increase in sound attenuation in the near-resonance range and may have a strong impact on sound dispersion in the liquid-bubble mixture at frequencies close to the resonance frequency of bubbles. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=sound%20propagation" title="sound propagation">sound propagation</a>, <a href="https://publications.waset.org/abstracts/search?q=gas%20bubbles" title=" gas bubbles"> gas bubbles</a>, <a href="https://publications.waset.org/abstracts/search?q=temperature%20effect" title=" temperature effect"> temperature effect</a>, <a href="https://publications.waset.org/abstracts/search?q=polymeric%20liquid" title=" polymeric liquid"> polymeric liquid</a> </p> <a href="https://publications.waset.org/abstracts/28205/liquid-temperature-effect-on-sound-propagation-in-polymeric-solution-with-gas-bubbles" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/28205.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">304</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2568</span> Importance of Solubility and Bubble Pressure Models to Predict Pressure of Nitrified Oil Based Drilling Fluid in Dual Gradient Drilling</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Sajjad%20Negahban">Sajjad Negahban</a>, <a href="https://publications.waset.org/abstracts/search?q=Ruihe%20Wang"> Ruihe Wang</a>, <a href="https://publications.waset.org/abstracts/search?q=Baojiang%20Sun"> Baojiang Sun</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Gas-lift dual gradient drilling is a solution for deepwater drilling challenges. As well, Continuous development of drilling technology leads to increase employment of mineral oil based drilling fluids and synthetic-based drilling fluids, which have adequate characteristics such as: high rate of penetration, lubricity, shale inhibition and low toxicity. The paper discusses utilization of nitrified mineral oil base drilling for deepwater drilling and for more accurate prediction of pressure in DGD at marine riser, solubility and bubble pressure were considered in steady state hydraulic model. The Standing bubble pressure and solubility correlations, and two models which were acquired from experimental determination were applied in hydraulic model. The effect of the black oil correlations, and new solubility and bubble pressure models was evaluated on the PVT parameters such as oil formation volume factor, density, viscosity, volumetric flow rate. Eventually, the consequent simulated pressure profile due to these models was presented. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=solubility" title="solubility">solubility</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20pressure" title=" bubble pressure"> bubble pressure</a>, <a href="https://publications.waset.org/abstracts/search?q=gas-lift%20dual%20gradient%20drilling" title=" gas-lift dual gradient drilling"> gas-lift dual gradient drilling</a>, <a href="https://publications.waset.org/abstracts/search?q=steady%20state%20hydraulic%20model" title=" steady state hydraulic model"> steady state hydraulic model</a> </p> <a href="https://publications.waset.org/abstracts/55577/importance-of-solubility-and-bubble-pressure-models-to-predict-pressure-of-nitrified-oil-based-drilling-fluid-in-dual-gradient-drilling" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/55577.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">275</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2567</span> Simulation of Ammonia-Water Two Phase Flow in Bubble Pump</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Jemai%20Rabeb">Jemai Rabeb</a>, <a href="https://publications.waset.org/abstracts/search?q=Benhmidene%20Ali"> Benhmidene Ali</a>, <a href="https://publications.waset.org/abstracts/search?q=Hidouri%20Khaoula"> Hidouri Khaoula</a>, <a href="https://publications.waset.org/abstracts/search?q=Chaouachi%20Bechir"> Chaouachi Bechir</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The diffusion-absorption refrigeration cycle consists of a generator bubble pump, an absorber, an evaporator and a condenser, and usually operates with ammonia/water/ hydrogen or helium as the working fluid. The aim of this paper is to study the stability problem a bubble pump. In fact instability can caused a reduction of bubble pump efficiency. To achieve this goal, we have simulated the behaviour of two-phase flow in a bubble pump by using a drift flow model. Equations of a drift flow model are formulated in the transitional regime, non-adiabatic condition and thermodynamic equilibrium between the liquid and vapour phases. Equations resolution allowed to define void fraction, and liquid and vapour velocities, as well as pressure and mixing enthalpy. Ammonia-water mixing is used as working fluid, where ammonia mass fraction in the inlet is 0.6. Present simulation is conducted out for a heating flux of 2 kW/m² to 5 kW/m² and bubble pump tube length of 1 m and 2.5 mm of inner diameter. Simulation results reveal oscillations of vapour and liquid velocities along time. Oscillations decrease with time and with heat flux. For sufficient time the steady state is established, it is characterised by constant liquid velocity and void fraction values. However, vapour velocity does not have the same behaviour, it increases for steady state too. On the other hand, pressure drop oscillations are studied. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubble%20pump" title="bubble pump">bubble pump</a>, <a href="https://publications.waset.org/abstracts/search?q=drift%20flow%20model" title=" drift flow model"> drift flow model</a>, <a href="https://publications.waset.org/abstracts/search?q=instability" title=" instability"> instability</a>, <a href="https://publications.waset.org/abstracts/search?q=simulation" title=" simulation"> simulation</a> </p> <a href="https://publications.waset.org/abstracts/66839/simulation-of-ammonia-water-two-phase-flow-in-bubble-pump" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/66839.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">262</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2566</span> A Nonlinear Stochastic Differential Equation Model for Financial Bubbles and Crashes with Finite-Time Singularities</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Haowen%20Xi">Haowen Xi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> We propose and solve exactly a class of non-linear generalization of the Black-Scholes process of stochastic differential equations describing price bubble and crashes dynamics. As a result of nonlinear positive feedback, the faster-than-exponential price positive growth (bubble forming) and negative price growth (crash forming) are found to be the power-law finite-time singularity in which bubbles and crashes price formation ending at finite critical time tc. While most literature on the market bubble and crash process focuses on the nonlinear positive feedback mechanism aspect, very few studies concern the noise level on the same process. The present work adds to the market bubble and crashes literature by studying the external sources noise influence on the critical time tc of the bubble forming and crashes forming. Two main results will be discussed: (1) the analytical expression of expected value of the critical time <tc> is found and unexpected critical slowing down due to the coupling external noise is predicted; (2) numerical simulations of the nonlinear stochastic equation is presented, and the probability distribution of Prob(tc) is found to be the inverse gamma function. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubble" title="bubble">bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=crash" title=" crash"> crash</a>, <a href="https://publications.waset.org/abstracts/search?q=finite-time-singular" title=" finite-time-singular"> finite-time-singular</a>, <a href="https://publications.waset.org/abstracts/search?q=numerical%20simulation" title=" numerical simulation"> numerical simulation</a>, <a href="https://publications.waset.org/abstracts/search?q=price%20dynamics" title=" price dynamics"> price dynamics</a>, <a href="https://publications.waset.org/abstracts/search?q=stochastic%20differential%20equations" title=" stochastic differential equations"> stochastic differential equations</a> </p> <a href="https://publications.waset.org/abstracts/120932/a-nonlinear-stochastic-differential-equation-model-for-financial-bubbles-and-crashes-with-finite-time-singularities" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/120932.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">132</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2565</span> Detecting Financial Bubbles Using Gap between Common Stocks and Preferred Stocks</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Changju%20Lee">Changju Lee</a>, <a href="https://publications.waset.org/abstracts/search?q=Seungmo%20Ku"> Seungmo Ku</a>, <a href="https://publications.waset.org/abstracts/search?q=Sondo%20Kim"> Sondo Kim</a>, <a href="https://publications.waset.org/abstracts/search?q=Woojin%20Chang"> Woojin Chang</a> </p> <p class="card-text"><strong>Abstract:</strong></p> How to detecting financial bubble? Addressing this simple question has been the focus of a vast amount of empirical research spanning almost half a century. However, financial bubble is hard to observe and varying over the time; there needs to be more research on this area. In this paper, we used abnormal difference between common stocks price and those preferred stocks price to explain financial bubble. First, we proposed the ‘W-index’ which indicates spread between common stocks and those preferred stocks in stock market. Second, to prove that this ‘W-index’ is valid for measuring financial bubble, we showed that there is an inverse relationship between this ‘W-index’ and S&P500 rate of return. Specifically, our hypothesis is that when ‘W-index’ is comparably higher than other periods, financial bubbles are added up in stock market and vice versa; according to our hypothesis, if investors made long term investments when ‘W-index’ is high, they would have negative rate of return; however, if investors made long term investments when ‘W-index’ is low, they would have positive rate of return. By comparing correlation values and adjusted R-squared values of between W-index and S&P500 return, VIX index and S&P500 return, and TED index and S&P500 return, we showed only W-index has significant relationship between S&P500 rate of return. In addition, we figured out how long investors should hold their investment position regard the effect of financial bubble. Using this W-index, investors could measure financial bubble in the market and invest with low risk. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=financial%20bubble%20detection" title="financial bubble detection">financial bubble detection</a>, <a href="https://publications.waset.org/abstracts/search?q=future%20return" title=" future return"> future return</a>, <a href="https://publications.waset.org/abstracts/search?q=forecasting" title=" forecasting"> forecasting</a>, <a href="https://publications.waset.org/abstracts/search?q=pairs%20trading" title=" pairs trading"> pairs trading</a>, <a href="https://publications.waset.org/abstracts/search?q=preferred%20stocks" title=" preferred stocks"> preferred stocks</a> </p> <a href="https://publications.waset.org/abstracts/57248/detecting-financial-bubbles-using-gap-between-common-stocks-and-preferred-stocks" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/57248.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">368</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2564</span> Household Low Temperature MS2 (ATCC15597-B1) Virus Inactivation Using a Hot Bubble Column Evaporator</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Adrian%20Garrido%20Sanchis">Adrian Garrido Sanchis</a>, <a href="https://publications.waset.org/abstracts/search?q=Richard%20Pashley"> Richard Pashley</a> </p> <p class="card-text"><strong>Abstract:</strong></p> The MS2 (ATCC15597-B1) virus was used as a surrogate to estimate the inactivation rates for enteric viruses when using a hot air bubble column evaporator (HBCE) system in the treatment of household wastewater. In this study, we have combined MS2 virus surface charging properties with thermal inactivation rates, using an improved double layer plaque assay technique, in order to assess the efficiency of the HBCE process for virus removal in water. When bubbling a continuous flow of dry air, at 200°C, only heats the aqueous solution in the bubble column to about 50°C. Viruses are not inactivated by this solution temperature, as confirmed separately from water bath heating experiments. Hence, the efficiency of the HBCE process for virus removal in water appeared to be caused entirely by collisions between the hot air bubbles and the virus organisms. This new energy efficient treatment for water reuse applications can reduce the thermal energy required to only 25% (about 113.7 kJ/L) of that required for boiling (about 450 kJ/L). <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=MS2%20virus%20inactivation" title="MS2 virus inactivation">MS2 virus inactivation</a>, <a href="https://publications.waset.org/abstracts/search?q=water%20reuse" title=" water reuse"> water reuse</a>, <a href="https://publications.waset.org/abstracts/search?q=hot%20bubble%20column%20evaporator" title=" hot bubble column evaporator"> hot bubble column evaporator</a>, <a href="https://publications.waset.org/abstracts/search?q=water%20treatment" title=" water treatment"> water treatment</a> </p> <a href="https://publications.waset.org/abstracts/84622/household-low-temperature-ms2-atcc15597-b1-virus-inactivation-using-a-hot-bubble-column-evaporator" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/84622.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">210</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2563</span> Investigation Bubble Growth and Nucleation Rates during the Pool Boiling Heat Transfer of Distilled Water Using Population Balance Model</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=V.%20Nikkhah%20Rashidabad">V. Nikkhah Rashidabad</a>, <a href="https://publications.waset.org/abstracts/search?q=M.%20Manteghian"> M. Manteghian</a>, <a href="https://publications.waset.org/abstracts/search?q=M.%20Masoumi"> M. Masoumi</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20Mousavian"> S. Mousavian</a> </p> <p class="card-text"><strong>Abstract:</strong></p> In this research, the changes in bubbles diameter and number that may occur due to the change in heat flux of pure water during pool boiling process. For this purpose, test equipment was designed and developed to collect test data. The bubbles were graded using Caliper Screen software. To calculate the growth and nucleation rates of bubbles under different fluxes, population balance model was employed. The results show that the increase in heat flux from q=20 kw/m2 to q=102 kw/m2 raised the growth and nucleation rates of bubbles. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=heat%20flux" title="heat flux">heat flux</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20growth" title=" bubble growth"> bubble growth</a>, <a href="https://publications.waset.org/abstracts/search?q=bubble%20nucleation" title=" bubble nucleation"> bubble nucleation</a>, <a href="https://publications.waset.org/abstracts/search?q=population%20balance%20model" title=" population balance model"> population balance model</a> </p> <a href="https://publications.waset.org/abstracts/2791/investigation-bubble-growth-and-nucleation-rates-during-the-pool-boiling-heat-transfer-of-distilled-water-using-population-balance-model" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/2791.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">476</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2562</span> Laminar Separation Bubble Prediction over an Airfoil Using Transition SST Turbulence Model on Moderate Reynolds Number</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Younes%20El%20Khchine">Younes El Khchine</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammed%20Sriti"> Mohammed Sriti</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A parametric study has been conducted to analyse the flow around S809 airfoil of a wind turbine in order to better understand the characteristics and effects of laminar separation bubble (LSB) on aerodynamic design for maximizing wind turbine efficiency. Numerical simulations were performed at low Reynolds numbers by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations based on C-type structural mesh and using the γ-Reθt turbulence model. A two-dimensional study was conducted for the chord Reynolds number of 1×10⁵ and angles of attack (AoA) between 0 and 20.15 degrees. The simulation results obtained for the aerodynamic coefficients at various angles of attack (AoA) were compared with XFoil results. A sensitivity study was performed to examine the effects of Reynolds number and free-stream turbulence intensity on the location and length of the laminar separation bubble and the aerodynamic performances of wind turbines. The results show that increasing the Reynolds number leads to a delay in the laminar separation on the upper surface of the airfoil. The increase in Reynolds number leads to an accelerated transition process, and the turbulent reattachment point moves closer to the leading edge owing to an earlier reattachment of the turbulent shear layer. This leads to a considerable reduction in the length of the separation bubble as the Reynolds number is increased. The increase in the level of free-stream turbulence intensity leads to a decrease in separation bubble length and an increase in the lift coefficient while having negligible effects on the stall angle. When the AoA increased, the bubble on the suction airfoil surface was found to move upstream to the leading edge of the airfoil, that causes earlier laminar separation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=laminar%20separation%20bubble" title="laminar separation bubble">laminar separation bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence%20intensity" title=" turbulence intensity"> turbulence intensity</a>, <a href="https://publications.waset.org/abstracts/search?q=S809%20airfoil" title=" S809 airfoil"> S809 airfoil</a>, <a href="https://publications.waset.org/abstracts/search?q=transition%20model" title=" transition model"> transition model</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a> </p> <a href="https://publications.waset.org/abstracts/179140/laminar-separation-bubble-prediction-over-an-airfoil-using-transition-sst-turbulence-model-on-moderate-reynolds-number" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/179140.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">83</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2561</span> A Bibliometric Analysis on Filter Bubble</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Misbah%20Fatma">Misbah Fatma</a>, <a href="https://publications.waset.org/abstracts/search?q=Anam%20Saiyeda"> Anam Saiyeda</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This analysis charts the introduction and expansion of research into the filter bubble phenomena over the last 10 years using a large dataset of academic publications. This bibliometric study demonstrates how interdisciplinary filter bubble research is. The identification of key authors and organizations leading the filter bubble study sheds information on collaborative networks and knowledge transfer. Relevant papers are organized based on themes including algorithmic bias, polarisation, social media, and ethical implications through a systematic examination of the literature. In order to shed light on how these patterns have changed over time, the study plots their historical history. The study also looks at how research is distributed globally, showing geographic patterns and discrepancies in scholarly output. The results of this bibliometric analysis let us fully comprehend the development and reach of filter bubble research. This study offers insights into the ongoing discussion surrounding information personalization and its implications for societal discourse, democratic participation, and the potential risks to an informed citizenry by exposing dominant themes, interdisciplinary collaborations, and geographic patterns. In order to solve the problems caused by filter bubbles and to advance a more diverse and inclusive information environment, this analysis is essential for scholars and researchers. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bibliometric%20analysis" title="bibliometric analysis">bibliometric analysis</a>, <a href="https://publications.waset.org/abstracts/search?q=social%20media" title=" social media"> social media</a>, <a href="https://publications.waset.org/abstracts/search?q=social%20networking" title=" social networking"> social networking</a>, <a href="https://publications.waset.org/abstracts/search?q=algorithmic%20personalization" title=" algorithmic personalization"> algorithmic personalization</a>, <a href="https://publications.waset.org/abstracts/search?q=self-selection" title=" self-selection"> self-selection</a>, <a href="https://publications.waset.org/abstracts/search?q=content%20moderation%20policies%20and%20limited%20access%20to%20information" title=" content moderation policies and limited access to information"> content moderation policies and limited access to information</a>, <a href="https://publications.waset.org/abstracts/search?q=recommender%20system%20and%20polarization" title=" recommender system and polarization"> recommender system and polarization</a> </p> <a href="https://publications.waset.org/abstracts/174333/a-bibliometric-analysis-on-filter-bubble" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/174333.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">118</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2560</span> Numerical Study of Laminar Separation Bubble Over an Airfoil Using γ-ReθT SST Turbulence Model on Moderate Reynolds Number</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Younes%20El%20Khchine">Younes El Khchine</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A parametric study has been conducted to analyse the flow around S809 airfoil of a wind turbine in order to better understand the characteristics and effects of laminar separation bubble (LSB) on aerodynamic design for maximizing wind turbine efficiency. Numerical simulations were performed at low Reynolds numbers by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations based on C-type structural mesh and using the γ-Reθt turbulence model. A two-dimensional study was conducted for the chord Reynolds number of 1×105 and angles of attack (AoA) between 0 and 20.15 degrees. The simulation results obtained for the aerodynamic coefficients at various angles of attack (AoA) were compared with XFoil results. A sensitivity study was performed to examine the effects of Reynolds number and free-stream turbulence intensity on the location and length of the laminar separation bubble and the aerodynamic performances of wind turbines. The results show that increasing the Reynolds number leads to a delay in the laminar separation on the upper surface of the airfoil. The increase in Reynolds number leads to an accelerated transition process, and the turbulent reattachment point moves closer to the leading edge owing to an earlier reattachment of the turbulent shear layer. This leads to a considerable reduction in the length of the separation bubble as the Reynolds number is increased. The increase in the level of free-stream turbulence intensity leads to a decrease in separation bubble length and an increase in the lift coefficient while having negligible effects on the stall angle. When the AoA increased, the bubble on the suction airfoil surface was found to move upstream to the leading edge of the airfoil, causing earlier laminar separation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=laminar%20separation%20bubble" title="laminar separation bubble">laminar separation bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence%20intensity" title=" turbulence intensity"> turbulence intensity</a>, <a href="https://publications.waset.org/abstracts/search?q=s809%20airfoil" title=" s809 airfoil"> s809 airfoil</a>, <a href="https://publications.waset.org/abstracts/search?q=transition%20model" title=" transition model"> transition model</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a> </p> <a href="https://publications.waset.org/abstracts/177425/numerical-study-of-laminar-separation-bubble-over-an-airfoil-using-gh-retht-sst-turbulence-model-on-moderate-reynolds-number" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/177425.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">70</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2559</span> Numerical Study of Laminar Separation Bubble Over an Airfoil Using γ-ReθT SST Turbulence Model on Moderate Reynolds Number</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=Younes%20El%20Khchine">Younes El Khchine</a>, <a href="https://publications.waset.org/abstracts/search?q=Mohammed%20Sriti"> Mohammed Sriti</a> </p> <p class="card-text"><strong>Abstract:</strong></p> A parametric study has been conducted to analyse the flow around S809 airfoil of wind turbine in order to better understand the characteristics and effects of laminar separation bubble (LSB) on aerodynamic design for maximizing wind turbine efficiency. Numerical simulations were performed at low Reynolds number by solving the Unsteady Reynolds Averaged Navier-Stokes (URANS) equations based on C-type structural mesh and using γ-Reθt turbulence model. Two-dimensional study was conducted for the chord Reynolds number of 1×105 and angles of attack (AoA) between 0 and 20.15 degrees. The simulation results obtained for the aerodynamic coefficients at various angles of attack (AoA) were compared with XFoil results. A sensitivity study was performed to examine the effects of Reynolds number and free-stream turbulence intensity on the location and length of laminar separation bubble and aerodynamic performances of wind turbine. The results show that increasing the Reynolds number leads to a delay in the laminar separation on the upper surface of the airfoil. The increase in Reynolds number leads to an accelerate transition process and the turbulent reattachment point move closer to the leading edge owing to an earlier reattachment of the turbulent shear layer. This leads to a considerable reduction in the length of the separation bubble as the Reynolds number is increased. The increase of the level of free-stream turbulence intensity leads to a decrease in separation bubble length and an increase the lift coefficient while having negligible effects on the stall angle. When the AoA increased, the bubble on the suction airfoil surface was found to moves upstream to leading edge of the airfoil that causes earlier laminar separation. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=laminar%20separation%20bubble" title="laminar separation bubble">laminar separation bubble</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulence%20intensity" title=" turbulence intensity"> turbulence intensity</a>, <a href="https://publications.waset.org/abstracts/search?q=S809%20airfoil" title=" S809 airfoil"> S809 airfoil</a>, <a href="https://publications.waset.org/abstracts/search?q=transition%20model" title=" transition model"> transition model</a>, <a href="https://publications.waset.org/abstracts/search?q=Reynolds%20number" title=" Reynolds number"> Reynolds number</a> </p> <a href="https://publications.waset.org/abstracts/178912/numerical-study-of-laminar-separation-bubble-over-an-airfoil-using-gh-retht-sst-turbulence-model-on-moderate-reynolds-number" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/178912.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">85</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2558</span> Gas Holdups in a Gas-Liquid Upflow Bubble Column With Internal</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=C.%20Milind%20Caspar">C. Milind Caspar</a>, <a href="https://publications.waset.org/abstracts/search?q=Valtonia%20Octavio%20Massingue"> Valtonia Octavio Massingue</a>, <a href="https://publications.waset.org/abstracts/search?q=K.%20Maneesh%20Reddy"> K. Maneesh Reddy</a>, <a href="https://publications.waset.org/abstracts/search?q=K.%20V.%20Ramesh"> K. V. Ramesh</a> </p> <p class="card-text"><strong>Abstract:</strong></p> Gas holdup data were obtained from measured pressure drop values in a gas-liquid upflow bubble column in the presence of string of hemispheres promoter internal. The parameters that influenced the gas holdup are gas velocity, liquid velocity, promoter rod diameter, pitch and base diameter of hemisphere. Tap water was used as liquid phase and nitrogen as gas phase. About 26 percent in gas holdup was obtained due to the insertion of promoter in in the present study in comparison with empty conduit. Pitch and rod diameter have not shown any influence on gas holdup whereas gas holdup was strongly influenced by gas velocity, liquid velocity and hemisphere base diameter. Correlation equation was obtained for the prediction of gas holdup by least squares regression analysis. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubble%20column" title="bubble column">bubble column</a>, <a href="https://publications.waset.org/abstracts/search?q=gas-holdup" title=" gas-holdup"> gas-holdup</a>, <a href="https://publications.waset.org/abstracts/search?q=two-phase%20flow" title=" two-phase flow"> two-phase flow</a>, <a href="https://publications.waset.org/abstracts/search?q=turbulent%20promoter" title=" turbulent promoter"> turbulent promoter</a> </p> <a href="https://publications.waset.org/abstracts/155124/gas-holdups-in-a-gas-liquid-upflow-bubble-column-with-internal" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/155124.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">106</span> </span> </div> </div> <div class="card paper-listing mb-3 mt-3"> <h5 class="card-header" style="font-size:.9rem"><span class="badge badge-info">2557</span> Bubble Point Pressures of CO2+Ethyl Palmitate by a Cubic Equation of State and the Wong-Sandler Mixing Rule</h5> <div class="card-body"> <p class="card-text"><strong>Authors:</strong> <a href="https://publications.waset.org/abstracts/search?q=M.%20A.%20Sedghamiz">M. A. Sedghamiz</a>, <a href="https://publications.waset.org/abstracts/search?q=S.%20Raeissi"> S. Raeissi</a> </p> <p class="card-text"><strong>Abstract:</strong></p> This study presents three different approaches to estimate bubble point pressures for the binary system of CO2 and ethyl palmitate fatty acid ethyl ester. The first method involves the Peng-Robinson (PR) Equation of State (EoS) with the conventional mixing rule of Van der Waals. The second approach involves the PR EOS together with the Wong Sandler (WS) mixing rule, coupled with the Uniquac Ge model. In order to model the bubble point pressures with this approach, the volume and area parameter for ethyl palmitate were estimated by the Hansen group contribution method. The last method involved the Peng-Robinson, combined with the Wong-Sandler Method, but using NRTL as the GE model. Results using the Van der Waals mixing rule clearly indicated that this method has the largest errors among all three methods, with errors in the range of 3.96–6.22 %. The Pr-Ws-Uniquac method exhibited small errors, with average absolute deviations between 0.95 to 1.97 percent. The Pr-Ws-Nrtl method led to the least errors where average absolute deviations ranged between 0.65-1.7%. <p class="card-text"><strong>Keywords:</strong> <a href="https://publications.waset.org/abstracts/search?q=bubble%20pressure" title="bubble pressure">bubble pressure</a>, <a href="https://publications.waset.org/abstracts/search?q=Gibbs%20excess%20energy%20model" title=" Gibbs excess energy model"> Gibbs excess energy model</a>, <a href="https://publications.waset.org/abstracts/search?q=mixing%20rule" title=" mixing rule"> mixing rule</a>, <a href="https://publications.waset.org/abstracts/search?q=CO2%20solubility" title=" CO2 solubility"> CO2 solubility</a>, <a href="https://publications.waset.org/abstracts/search?q=ethyl%20palmitate" title=" ethyl palmitate"> ethyl palmitate</a> </p> <a href="https://publications.waset.org/abstracts/2308/bubble-point-pressures-of-co2ethyl-palmitate-by-a-cubic-equation-of-state-and-the-wong-sandler-mixing-rule" class="btn btn-primary btn-sm">Procedia</a> <a href="https://publications.waset.org/abstracts/2308.pdf" target="_blank" class="btn btn-primary btn-sm">PDF</a> <span class="bg-info text-light px-1 py-1 float-right rounded"> Downloads <span class="badge badge-light">474</span> </span> </div> </div> <ul class="pagination"> <li class="page-item disabled"><span class="page-link">&lsaquo;</span></li> <li class="page-item active"><span class="page-link">1</span></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=bubble%20points&page=2">2</a></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=bubble%20points&page=3">3</a></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=bubble%20points&page=4">4</a></li> <li class="page-item"><a class="page-link" href="https://publications.waset.org/abstracts/search?q=bubble%20points&page=5">5</a></li> <li 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