Mechanism of the Initial States of a Bubble Formation and Departure from a Heated Surface in a Subcooled Flow

Abstract

Growth of a nonisothermal bubble on a heated horizontal surface in a subcooled flow is studied to determine the significance of different heat transfer mechanisms on the bubble growth. The heat transfer mechanisms that are considered are (1) microlayer evaporation, (2) transient thermal boundary layer conduction, and (3) bubble surface evaporation and condensation. The results indicate that a different heat transfer mechanism dominates the bubble growth at different stages of the bubble growth. And, the temperature gradient inside the bubble decreases after bubble liftoff in high Reynolds numbers. The results also show an oscillatory heat flux during the initial stages of the bubble growth.