Effect of interlaced wettability on horizontal copper cylinders in nucleate pool boiling

Abstract

This study investigated horizontal copper cylinder surfaces with two mixed types of wettability in pool boiling heat transfer. Specifically, the interfaces between two surfaces with superhydrophilic and hydrophobic wettability were examined (these surface interfaces are called “interlaced lines”). The experimental results indicated that the number of interlaced lines and ratio of the two surface wettabilities affected the wall superheat and heat transfer performance of the surfaces. CCD images of the surfaces showed that the bubble dynamics at the interface line are predictors of the nucleate boiling behavior. Furthermore, the images revealed the difference in the bubble dynamics between the upper and bottom surfaces. Temperature measurements proved that the wall superheat at the upper surface was higher than that at the bottom surface. The experimental results indicated that the bubble dynamics on the surface are a critical factor determining the heat convection conditions of nucleate boiling.