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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 Navier-Stokes equations to consider surface tension, viscosity, gravity and phase change are discussed in detail. The governing equations are solved using finite difference method. In the present work, investigations on the effect of thermal conductivity and latent heat of vaporization of liquid on heat transfer in a 44 µm thick liquid film containing vapor bubble with droplet impact is investigated. The importance of thermal conductivity and latent heat of vaporization of liquid on heat transfer is identified. The variation of heat flux with thermal conductivity and latent heat is plotted. The computed liquid and vapor interface, velocity vector and temperature distributions at different time instants are also visualized for better understanding of the heat removal.

A closed loop spray cooling test setup is established for the cooling of high heat flux heat sources. Eight miniature nozzles (in a multi-nozzle plate) are used to generate a spray array targeting at a 1×2 cm2 cooling surface. FC-87, FC-72, methanol and water are used as the working fluids. Thermal performance data for the multi-nozzle spray cooling in the confined and closed system are obtained at various operating temperatures, nozzle pressure drops (from 0.69 bar to 3.10 bar) and heat fluxes. It is exhibited that the spray cooler can reach the critical heat fluxes of 90 W/cm2 with fluorocarbon fluids and 490 W/cm2 with methanol. For water, the critical heat flux is higher than 500 W/cm2. The air purposely introduced in the spray cooling system with FC-72 fluid has a significant influence on heat transfer characteristics of the spray over the cooling surface.