Numerical simulation of bubble growth in film boiling using a coupled level-set and volume-of-fluid method

A coupled level-set and volume-of-fluid method is presented for modeling incompressible two-phase flows with surface tension. The coupled algorithm conserves mass and captures the complicated interfaces very accurately. A planar simulation of bubble growth is performed in water at near critical pressure for different degrees of superheat. The effect of superheat on the frequency of bubble formation has been analyzed. In addition, simulation of film boiling and bubble formation is performed in refrigerant R134a at near critical and far critical pressures. The effect of saturation pressure on the frequency of bubble formation has also been studied. A deviation from the periodic bubble release is observed in the case of superheat beyond 15K in water. The effect of heat flux on the instability has also been analyzed. It is found that for water at near critical condition, a decrease in superheat from 15to10K leads to oscillations with subharmonics influencing the time period of the ebullition cycle.