EVAPORATION MOMENTUM FORCE ON A BUBBLE UNDER ASYMMETRIC TEMPERATURE CONDITIONS

Recent literature claims that boiling performance can be significantly improved by using evaporation momentum force to control the trajectory of a bubble. This approach merits a detailed investigation into evaporation momentum force and its effect on bubble growth and bubble trajectory. In this paper an expression for evaporation momentum pressure experienced by a bubble is determined. This is incorporated into a well established bubble growth model (Mikic-Rohsenow) to evaluate the effect of evaporation momentum pressure on bubble growth rate. The effect of evaporation momentum force on a bubble growing in asymmetric temperature field is then studied and the resultant trajectory is evaluated. The results are compared with experimental data of bubble trajectory subjected to an asymmetric temperature condition. The final results suggest that the evaporation momentum pressure in the vicinity of contact line can significantly change the bubble trajectory, and surfaces designed to exploit this effect seem to be promising for boiling enhancement.