Abstract

In pool boiling applications, appropriate surface properties of the heating surface are crucial for improving the heat transfer. In this study, two different Al₂O₃ nano-structured surfaces were fabricated using dip-coating method by controlling coating thickness, and adopted to conduct pool boiling experiments with R-141b. Prepared Al₂O₃ nano-structured surfaces were characterized by scanning electron microscopy (SEM), elemental dispersive spectroscopy (EDS), ellipsometer, contact angle meter, and 2D profilometer to investigate the surface morphology, elemental composition, thickness, angle of contact, and surface roughness, respectively. Based on the surface characterization and boiling curves, the effects of coating thickness (300 nm and 400 nm) on the pool boiling heat transfer were examined. The heat transfer coefficient (HTC) of Al₂O₃ nano-structured surface (S2) was the highest, followed by those of Al₂O₃nano-structured surface (S1), and plain copper surface. The outstanding heat transfer performance of Al₂O₃ nano-structured surfaces is mainly associated with enhanced surface wettability and increased active nucleation site density.

中文翻译：

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R-141b在浸涂法制备的Al2O3纳米结构表面上的饱和池沸腾传热

摘要

在池沸腾应用中，加热表面适当的表面特性对于改善传热至关重要。本研究采用 浸涂法通过控制涂层厚度制备了两种不同的Al ₂ O _{3纳米结构表面，并采用R-141b进行池沸腾实验。}通过扫描电子显微镜（SEM）、元素色散光谱（EDS）、椭偏仪、接触角计和二维轮廓仪对制备的Al ₂ O ₃ 纳米结构表面进行表征，研究其表面形貌、元素组成、厚度、接触角、和表面粗糙度。根据表面特征和沸腾曲线，研究了涂层厚度（300 nm 和 400 nm）对池沸腾传热的影响。_{Al 2} O ₃纳米结构表面(S2)的传热系数(HTC) 最高，其次是Al ₂ O ₃纳米结构表面(S1)和普通铜表面。_{Al 2} O ₃纳米结构表面出色的传热性能主要与增强的表面润湿性和增加的活性成核位点密度有关。