TY - JFULL AU - M. Wasy Akhtar PY - 2018/7/ TI - Multi-Modal Film Boiling Simulations on Adaptive Octree Grids T2 - International Journal of Mechanical and Mechatronics Engineering SP - 654 EP - 659 VL - 12 SN - 1307-6892 UR - https://publications.waset.org/pdf/10009159 PU - World Academy of Science, Engineering and Technology NX - Open Science Index 138, 2018 N2 - Multi-modal film boiling simulations are carried out on adaptive octree grids. The liquid-vapor interface is captured using the volume-of-fluid framework adjusted to account for exchanges of mass, momentum, and energy across the interface. Surface tension effects are included using a volumetric source term in the momentum equations. The phase change calculations are conducted based on the exact location and orientation of the interface; however, the source terms are calculated using the mixture variables to be consistent with the one field formulation used to represent the entire fluid domain. The numerical model on octree representation of the computational grid is first verified using test cases including advection tests in severely deforming velocity fields, gravity-based instabilities and bubble growth in uniformly superheated liquid under zero gravity. The model is then used to simulate both single and multi-modal film boiling simulations. The octree grid is dynamically adapted in order to maintain the highest grid resolution on the instability fronts using markers of interface location, volume fraction, and thermal gradients. The method thus provides an efficient platform to simulate fluid instabilities with or without phase change in the presence of body forces like gravity or shear layer instabilities. ER -