Study on characteristics of thermal hydraulics in porous media based on microscale infrared and visible observation

(The effect of wettability improvement on the heat transfer performance)

Abstract

This paper reports the characteristics of thermo-fluid behavior in a wick that is fine porous structure and the effect of wick’s wettability improvement on the heat transfer coefficient. In this study, visualization of liquid-vapor interface behavior on the surface of the wick with microscopic infrared thermography and microscope was conducted. 2 wicks were made by stainless steel (SS). The acid treatment with hydrochloric acid was processed to one wick in order to improve the wettability. Contact angle changed from 10.7° to 0 ° after acidizing. As results, heat transfer coefficient of the wick with acid treatment became higher at 5.0~5.5W/cm². The reason of this trend is discussed based on the observation results.