Heat transfer mechanisms in pool boiling

摘要

Pool boiling is a heat transfer mechanism carrying a phase transition from liquid to vapor. However, the exact characteristics of pool boiling are obscure because of the lack of the theoretical approach method. We have proposed a statistical thermodynamic heat transfer theory which is applicable to the heat transfer mechanisms of both conduction and internal convection. We here apply the heat transfer theory to pool boiling as an explicit illustration to understand the kinetics of phase transition mechanisms at the interface of two different phase materials. Three variable separation constants stand for particle number constants and play the key roles in exploiting the distinct boiling mechanisms. The theory accounts for the four boiling mechanisms of natural convection, nucleate boiling, transition boiling, and film boiling in pool boiling. It is able to match heat fluxes in wide ranges of temperature, time, and space. Particularly, the heat flux curve is sketched as a function of excess temperature between wall temperature and saturation temperature in the four regimes. Three limiting heat fluxes and four activation temperatures are employed as input parameters. Theoretical heat flux-temperature curves agree with experimental heat flux profiles in a significantly broader range of temperature than those from any existing theories.