Study of lateral merger of vapor during nucleate pool boiling

In the present work the bubble dynamics and heat transfer associated with lateral bubble merger during transition from partial to fully developed nucleate boiling is studied numerically. Complete Navier-Stokes equation in three dimensions along with the continuity and energy equations are solved using the SIMPLE method. The liquid vapor interface is captured using the Level-Set technique. Calculations are carried out for multiple bubble mergers in a line and also in a plane and the bubble dynamics and wall heat transfer are compared to that for a single bubble. The results show that merger of multiple bubbles significantly increases the overall wall heat transfer This enhanced wall heat transfer is caused by trapping of liquid layer between the bubble bases during merger and by drawing of cooler liquid towards the wall during contraction after merger. Good agreement with data from experiments is found in bubble growth rate and bubble shapes obtained from numerical simulations.