Computational Study of Subcooled Pool Boiling: Effects on Heat Flux and Bubble Dynamics

In the past, saturated pool boiling has been the primary focus of research, while subcooled pool boiling has received less attention. As a result, the understanding of subcooled pool boiling physics remains limited. The present work examines the effect of subcooling on both heat flux and bubble dynamics by conducting direct numerical simulations (DNS) of pool boiling using an in-house Navier Stokes solver. Liquid-vapor interface is tracked using level set technique. Ghost-fluid formulation is considered to account for sharp jumps in pressure, velocity, and temperature across multiphase boundaries. Two sets of computations have been conducted using FC72 as a working fluid. In the first set, bulk liquid temperature was varied while the rest of parameters were held constant. In the second set, Stefan's number was maintained constant. All cases show that subcooled pool boiling affects boiling curve, heat flux, and bubble dynamics. Computational results were compared to available empirical correlations. Furthermore, details of the flow field reveal flow structures in the form of mushroom-like vortices due to near wall interactions, while vortex ring patterns were observed further away from the wall. Variation of Stefan number revealed negligible effect.