Modeling of Spray Cooling: Convective Flow Effect on Vapor Bubble Dynamics and Heat Transfer

Abstract

‡Spray cooling with phase change has the advantage of relatively large amount of latent heat of vaporization release. The two-phase flow modeling is done using the level set method to identify the interface of vapor and liquid. The modifications to the incompressible NavierStokes equations to consider surface tension, viscosity, gravity and phase change are discussed in detail. The equations are solved using finite difference method. In our previous works, the droplet impact on thin liquid film with growing vapor bubbles and the corresponding heat transfer were reported for varying droplet velocities, liquid to vapor density ratios and for varying vapor bubble sizes. In this work the effect of convective flow on vapor bubble in a thin liquid film and the corresponding heat transfer is systematically investigated. The computed average Nusselt number as a function of time is plotted for different horizontal velocity of the flow. The computed liquid and vapor interface and temperature distributions are also visualized for better understanding of the heat removal. This study helps to understand the influence of convective flow on heat transfer in a liquid film with vapor bubble growing and illustrates the importance of considering the convective flow effect with droplet impact for future spray cooling modeling studies.