Pool Boiling of NOVEC-649 on Microparticle-Coated and Nanoparticle-Coated Surfaces
Zhen Cao, Zan Wu, Bengt Sundén
Abstract
In this study, microparticle coatings and nanoparticle coatings were fabricated on copper surfaces by an electrochemical deposition method and an electrophoretic deposition method, respectively. Pool boiling of NOVEC-649 was experimentally studied on the coated surfaces, concerning heat transfer, bubble dynamics, and critical heat fluxes. Compared with a smooth surface, heat transfer coefficients and critical heat flux (CHF) were improved, achieving a maximum heat transfer enhancement of 460% on the nanoparticle-coated surface and a maximum CHF enhancement of 60% on the microparticle-coated surface. Based on high speed visualizations, bubble departure diameters were measured and compared with several correlations, and then the heat transfer was analyzed by a mechanistic model, considering natural convection, transient heat conduction and microlayer evaporation. The mechanistic model demonstrated a good ability to predict the present results. In addition, wickability, representing a liquid supplement ability, was measured, indicating that the wickability enhancement was probably responsible for the CHF improvement.