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.

摘要

在这项研究中，分别通过电化学沉积方法和电泳沉积方法在铜表面上制备了微粒涂层和纳米粒子涂层。在涂层表面上实验研究了 NOVEC-649 的池沸腾，涉及传热、气泡动力学和临界热通量。与光滑表面相比，传热系数和临界热通量（CHF）得到改善，纳米粒子包覆表面的最大传热增强为 460%，微粒包覆表面的 CHF 最大增强为 60%。基于高速可视化，测量气泡离开直径并与几个相关性进行比较，然后通过机械模型分析传热，考虑自然对流，瞬态热传导和微层蒸发。机械模型显示出良好的预测当前结果的能力。此外，测量了代表液体补充能力的芯吸能力，表明芯吸能力增强可能是 CHF 改善的原因。