Geometric Effects on Critical Heat Flux on Horizontal Microporous Coatings

Abstract

This study aims to understand the effects of the geometric parameters of microporous coatings on the critical heat flux through systematic series of experimental studies. The test results indicated that critical heat flux of microporous coated surfaces is strongly dependent on the coating thickness, volumetric porosity, and pore size. For a given heating area, the critical heat flux mechanism was found to be distinguished by the microporous coating thickness. In addition, the optimal volumetric porosity was found to exist when the mesh size and coating thickness were held nearly constant. The wire diameter was found to play an important role in determining critical heat flux during the boiling process, which is consistent with existing observations, but has not previously been specifically stated. The observed effects of the various geometric parameters of the porous coating on the critical heat flux, clearly illustrated by the capillary fluid flow inside the porous coating, play a significant role in the determination of critical heat flux. Currently available critical heat flux models were not found to accurately predict the test data in this study, primarily due to the aforementioned important factor.