Abstract

Industrial shell and tube heat exchangers require often pipes of considerable length. The surface treatment of such tubes to enhance heat transfer parameters of the equipment must be cheap and simple in manufacturing. Two kinds of tube surface treatment are compared: sandblasting and machining. The tubes with OD = 10 mm, ID = 6 mm, and 625 mm long were tested within a bundle of horizontal tubes installed in a rectangular evaporator shell. Hot water pumped through bundle tubes used as a heat carrier. Refrigerant R21 at the pressure of \(\sim\)3 bara is used as working liquid. Tests have been performed at \(Re\) numbers from 500 to 1500. The micro-rough tubes (machined duralumin tube, sandblasted copper tube) provide considerable heat transfer enhancement at transition to bubble boiling. At low heat fluxes (evaporation regime) heat transfer on these tubes are close to plain tubes.

中文翻译：

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水平粗管膜灌蒸发沸腾传热

摘要

工业管壳式热交换器通常需要相当长的管道。为了提高设备的传热参数而对此类管进行的表面处理必须便宜且制造简单。比较了两种管材表面处理：喷砂和机械加工。外径 = 10 毫米、内径 = 6 毫米、长 625 毫米的管子在安装在矩形蒸发器外壳中的一束水平管内进行测试。热水通过用作热载体的束管泵送。采用压力为 \(\sim\) 3 bara 的制冷剂R21 作为工作液体。测试已在 500 至 1500 的Re 数下进行。微型粗糙管（机加工硬铝管、喷砂铜管）在过渡到气泡沸腾时提供了相当大的传热增强。在低热通量（蒸发状态）下，这些管上的传热接近于普通管。