Enhanced Surfaces Used in Research on Flow Boiling Heat Transfer in Minichannels

Abstract

This paper reviews enhanced surfaces used to study boiling heat transfer in minichan-nels with rectangular cross-sections. Experiments were conducted for refrigerants flowing along a vertical minichannel, asymmetrically heated by one of the enhanced surfaces. The enhanced surfaces used in the experiments were the following: laser textured and vibration-assisted laser textured surfaces with regular cavities, electro-discharge machined surfaces with irregular cavities, fibrous surfaces with capillary-porous structures, and powder-coated surfaces. Heat transfer efficiency was evaluated based on local heat transfer coefficients calculated at the heated surface-fluid interface in the minichannel. Vibration-assisted laser surface texturing provided the most efficient heat transfer compared to the other enhanced surfaces and the smooth surface.