NUMERICAL SIMULATION OF THREE BUBBLES INTERACTION DURING FLOW BOILING OF WATER IN MICROCHANNEL

A numerical study has been performed to analyze the wall heat transfer mechanisms during growth of three vapor bubbles inside a microchannel. Flow through microchannel is a subject of extensive study due to its widespread applications in thermal engineering and biological sciences. The microchannel that was used here is 200 mu m square cross section and vapor bubbles begins to nucleate at certain distance apart, with liquid coming in through the channel inlet. The complete Navier-Stokes equations along with continuity and energy equations are solved using the SIMPLER method. The liquid vapor interface is captured using the level set technique. The numerical result show that bubbles with the lowest contact angle and high wall superheat temperature resulted in the highest wall heat transfer. Reynolds number don't have any effect in the microchannel flow boiling. Finally, a comparative study was done between single bubble, two bubbles and three bubbles inside a microchannel. Experiment was done with placing bubbles at different distances, some are close to each other which eventually merged together and some are far enough which never merged. Heat transfer increases when the bubbles do not merge together compared to when they do merge.