Condensation heat transfer coefficient for rectangular multiport microchannels at high ambient temperature
Condensation heat transfer coefficient for rectangular multiport microchannels at high ambient temperature
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DOI：
10.1016/j.ijheatmasstransfer.2019.04.048
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发表时间：
2019-08-01
影响因子：
5.2
通讯作者：
Ricco, Pierre
中科院分区：
文献类型：
--
作者：
Al-Bakri, Basim A. R.;Ricco, Pierre
对水力直径分别为0.52 mm和1.26 mm的水平矩形多孔铝微通道内混合工质R-410A的局部换热系数进行了实验计算。制冷剂在接近临界的压力下流动，冷却空气在高温下流动，这与炎热的气候相适应。实验在自制的实验装置上进行，采用微箔传感器测量局部冷凝热流。换热系数随单位面积质量流量和蒸汽质量的增大而增大，随环境温度的升高而减小。文献中的关联式并不能令人满意地预测我们的实验数据，因为我们的极端工作条件是高压和高冷却空气温度。从而得到了一个新的关联式，成功地计算了高压高温条件下冷凝环空流区的努塞尔数。(C)2019爱思唯尔有限公司。保留所有权利。
We experimentally compute the local heat transfer coefficient of blend refrigerant R-410A condensing inside horizontal rectangular multiport aluminium microchannels with hydraulic diameters equal to 0.52 mm and 1.26 mm. The refrigerant flows at near-critical pressure and the cooling air flows at high temperatures proper of hot climates. The experiments are conducted in a bespoke experimental facility and micro-foil sensors are used to measure the local condensation heat flux. The heat transfer coefficient is found to increase with the mass flow rate per unit area and the vapour quality and to decrease with the ambient temperature. Correlations available in the literature do not predict our experimental data satisfactorily because of our extreme operating conditions of high pressure and high cooling air temperature. A novel correlation is therefore obtained to successfully compute the Nusselt number for the condensing annular flow regime in our high pressure and high temperature conditions. (C) 2019 Elsevier Ltd. All rights reserved.