Experimental Study of Nucleate Boiling Performance on Several Types of the Mixed-Wettability Pattern Surface by Micro/Milli-Sized Hydrophobic Patterns

Abstract

To increase the nucleate boiling efficiency, many nucleate boiling experiments have been conducted and could get brilliant and challengeable results. A consensus was that CHF and heat transfer were affected by a modified heating surface which change the micro roughness, thermophysical properties of heating surface, or the wettability. Of the many parameters, the wettability study is regarded as the most powerful factor. For finding the optimized condition at the nucleate boiling (high heat transfer and high CHF), we design the special heaters to examine how two materials, which have different wettabilities, affect the boiling phenomena. The special heaters have several types of hydrophobic patterns which have the precise size because they were made by MEMS techniques on the silicon oxide surface. In the experiments with patterned surface, hydrophobic dots lead to an early bubble inception and induce the better heat transfer. These experiments are compared with classic and recent models for bubble inception. The all experiments are conducted under the saturated pool boiling condition with distilled water at 1 atm pressure. The peculiar Teflon (AF1600) is used as the hydrophobic material. The hydrophilic part is performed by silicon oxide through the furnace procedure. The experiments using the micro-sized patterns and milli-sized patterns are performed, and the results are compared with the reference surface. These mixed-wettability studies are expected to induce the development of the nucleate boiling condition.