Theoretical and Experimental Analysis of Increasing Pressure During Pool-Boiling

Abstract

The thermo-fluid properties of water change at high pressure. The performance of high pressure pool boiling greater than 50 Psi has not been studied widely. The aim of this paper is to analyze the experimental data to describe the effect of increasing pressure during pool boiling. Hsu’s correlation was used to predict the active nucleation sites. The maximum and minimum radii of the active nucleation sites were determined as a function of heat flux or degree of wall superheats over a wide range of pressures. The bubble dynamics are discussed using the predicted values of fundamental boiling quantities such as bubble departure diameter, active nucleation site density and bubble release frequency. The thickness of the boundary layer was assumed to be 30 microns. Rohsenow’s and Forster’s correlations were used to predict the pool boiling curve for different pressures. The comparison was made with the experimental data for water of a plain copper surface of increasing pressure. The parametric trend provides fundamental insight and explains how the system pressure can maximize the boiling efficiency of new generation boilers.