Pool boiling review: Part II – Heat transfer enhancement

Abstract

Copyright © 2021 The Author(s). Heat transfer enhancement by surface modification has been extensively studied in the last twenty years. However, there remains a large discrepancy among researchers on the performance of enhanced surfaces even for the same fluid and surface preparation technique. The reasons of this discrepancy are not understood and are not discussed in past papers, including paper reviews. Part II of this two-part paper aims to present a detailed assessment of pool boiling heat transfer enhancement, relating this to Part I [1], which presented a critical assessment of fundamental concepts of heterogeneous nucleation. Current challenges in evaluating the performance of enhanced surfaces is first discussed. The performance of smooth and roughened surfaces is then discussed and the effect of fluid type is explained. Pool boiling data of two fluids, namely water and FC-72, on two enhanced substrate materials, i.e. copper and silicon were digitized and assessed in order to elucidate the reason for the discrepancy in published works and present future recommendations for heat transfer enhancement. The heat transfer enhancement mechanisms adopted by researchers were presented and critically discussed and compared. The paper contributes to the understanding of the effect of fluid-surface combinations and suggest guidelines for researchers to consider when evaluating the performance of enhanced surfaces. This will help the research community and industry to conclude on the best surface structure and surface manufacturing technique matching particular fluid of interest.