An experimental investigation on pool boiling heat transfer enhancement using sol-gel derived nano-CuO porous coating

Abstract

This paper presents an experimental investigation aimed at studying the influence of nano-CuO coating on the pool boiling heat transfer enhancement of SS 316 LN stainless steel. The coating was developed using the sol-gel dip coating technique. The Scanning Electron Microscopic and X-Ray Diffraction apparatus were used to analyze morphological and structural characteristics of the coating. The complex interaction of coating process parameters on the boiling heat transfer coefficient was studied using the concept of design of experiment. The results reveal as much as 30% increase in the boiling heat transfer coefficient for the sol-gel derived CuO coated boiling surface compared to its uncoated counterpart. The coating was found to tailor the porosity, roughness and wettability of the surface. The heat transfer coefficient increased with an increase in porosity, roughness and decrease in wettability of the boiling surface. Analysis of variance results revealed that the molar concentration of the CuO sol was the most significant parameter influencing the heat transfer coefficient while sintering temperature was the least significant parameter.