A CFD Modeling of Subcooled Pool Boiling

Subcooled pool boiling is of immense importance in many industrial and engineering systems because of its great heat transfer coefficient in comparison with other heat transfer mechanisms. However it is one of the most complicated two-phase phenomena due to, for example, the simultaneous liquid/vapor motion at the same time with heat and mass transfer across the phase interfaces, distorted and deformable phase interface geometry with complicated bubble breakup/coalescence mechanisms etc. As the accuracy of the CFD simulation of two-phase flows has much improved, numerical study of subcooled pool boiling two-phase flow by using the CFD approach is desirable. To incorporate experimental and numerical studies of subcooled boiling, the objective of this study is to setup a numerical modeling of the subcooled pool boiling in a vertical pipe by using the CFD approach. The numerical setup is based on the physical experimental model developed in our previous study. For the numerical simulation of subcooled pool boiling and wall boiling, the extended RPI boiling model is exploited in the framework of the two-fluid CFD approach. Test simulations by using the numerical setup have been carried out for three cases: a single air bubble rising in still water, a vapor Taylor bubble rising in saturated still water, and a vapor bubble rising and condensing in subcooled still water. Evaluation of the model setup has been clarified. An initial simulation of subcooled pool boiling has also been demonstrated.