Dynamic Model of Enhanced Boiling Heat Transfer on Porous Surfaces—Part II: Analytical Modeling

Abstract

Based on the experimental results reported in Part I, an analytical model of the dynamic cycle of bubble formation is proposed. The cycle consists of a waiting period and a bubble growth period; in the former the pressure in the tunnel is increased due to evaporation from internally held meniscuses and in the latter a certain amount of pool liquid is sucked in the tunnel to be subsequently evaporated. The equations are formulated with the adoption of a moderate number of empirical constants. Their solutions give the predictions of latent heat flux due to internal evaporation, population density of active sites, and frequency of bubble formation. The population density is then used to estimate convective heat flux on the outer surface from the empirical correlation established in Part I. The analytical predictions are compared with the experimental data of Part I. The results are encouraging and indicate the course of future study to implement the model.