Abstract

This paper presents experimental results on heat transfer efficiency on a flat circular heat-release surface modified using additive technology. A porous plate 500 \(\mu\)m thick, 3D-printed from copper spherical granules with an average diameter of 50 \(\mu\)m, was fixed by means of resistance soldering on a heat-release brass surface of 20 mm in diameter. The heat transfer was investigated at boiling in liquid Freon R21 under free convection conditions for the heat flux density varying from 200 to \(4.5\cdot 10^{5}\) W/m². In different series of the experiments, the reduced pressure varied within 0.027–0.064. The experiments have shown that under conditions of activated nucleation sites, the heat transfer coefficient for a modified surface 4–5 times exceeds that for an unmodified surface. The greatest effect is observed in the region of small and medium values of the heat flux density.

中文翻译：

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放热面改性对氟利昂自由对流下核沸腾传热的影响

摘要

本文介绍了使用添加剂技术改性的扁平圆形散热表面的传热效率的实验结果。一块 500 \(\mu\) m 厚的多孔板 ，由平均直径为 50 \(\mu\) m 的铜球形颗粒 3D 打印而成 ，通过电阻焊接固定在 20 微米的散热黄铜表面上毫米直径。研究了在液体氟利昂 R21 中沸腾时在自由对流条件下的热传递，热通量密度从 200 到\(4.5\cdot 10^{5}\)  W/m ². 在不同系列的实验中，减压在 0.027-0.064 之间变化。实验表明，在活化成核位点的条件下，改性表面的传热系数是未改性表面的 4-5 倍。在热通量密度的中小值区域观察到最大的影响。