Two-phase Euler-Euler solver for simulation of subcooled nucleate boiling

Development and validation of an OpenFOAMr based two-phase solver is described. The twoPhaseEulerFoam solver of OpenFOAMr version 1.7 was used as a starting point, where enthalpy equations for two phases were added using phase-intensive formulation of the transport equations along with OpenFOAMr thermo physical models. The same phaseintensive approach was adopted for the turbulence model equations. Closure laws commonly used in literature for modelling dispersed bubbly air flow in water were added in the solver. For modelling dispersed bubbly flow in a liquid a wide selection of user-selectable interfacial force models were implemented, including the wall lubrication force the models of Antal and Frank and the turbulent dispersion models by Lopez de Bertodano and Burns et al. Thermal phase change terms and an implementation of the RPI model for subcooled nucleate boiling were added. The RPI model was implemented in the OpenFOAMr multiphase solver by using models found in open literature. The wall surface area is divided into area fractions affected and unaffected by boiling, which are calculated from wall nucleation site density and bubble departure diameter. The area fractions are used for modelling the convective heat transfer and the quenching heat transfer. Interfacial heat transfer is modelled with a tworesistance model, including condensation and evaporation of the vapour bubbles. The boiling model was validated against publicly available data from the DEBORA experiment and compared to results obtained with a commercial code