Experimental Study on the Velocity of Isolated Liquid Films in Spray Cooling
The liquid film is the direct carrier and thermal resistance of the complex heat transfer process in spray cooling,and thus it is important for understanding the heat transfer mechanism.However,the evolution of liquid films on the surface still remains unclear owing to the interactions and disturbances between the atomized droplets and the thin films with high turbulences.In this study,the liquid film dynamics of an HFE-7000 spray in a two-phase cooling regime on a smooth surface were quantitatively captured,including the film morphology,film velocity,and equivalent diameter under different inlet pressures,and the heat fluxes.The distributions of the atomized droplet velocities under different inlet pressures were measured and the related empirical correlation was proposed.Then,the velocities and the equivalent diameters of the isolated liquid film were measured,and the Weber numbers were obtained after that.Finally,based on the relationship between the atomized droplets and the liquid film,in combination with the thermal boundaries of the surface temperature gradient,a series of prediction methods for the surface-averaged velocity and the Weber number of the isolated films were proposed,via which the related predicting limitations were 21.52％and 24.3％respectively.
spray coolingliquid film flowliquid film velocityweber number
NETL
NSTL
万方数据
维普
