Effect of aspect ratio on flow boiling characteristics in microchannels
Effect of aspect ratio on flow boiling characteristics in microchannels
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DOI：
10.1016/j.ijheatmasstransfer.2020.120587
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发表时间：
2021-01
影响因子：
5.2
通讯作者：
Ali H. Al-Zaidi;M. Mahmoud;T. Karayiannis
中科院分区：
文献类型：
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作者：
Ali H. Al-Zaidi;M. Mahmoud;T. Karayiannis
实验研究了通道长径比对HFE-7100在铜多通道热沉中流动沸腾特性（流型、传热和压降）的影响。三个散热器的底部面积为500平方毫米，通道水力直径为0.46毫米和通道的纵横比（通道宽度与通道高度的比率）为0.5，1.0和2.0进行了测试。通道底面的平均表面粗糙度在三种散热器中几乎相同，测量值分别为0.271、0.286和0.304 µm。在质量通量范围为50至250 kg/m2 s、壁热通量范围为9.6至191.6 kW/m2、系统压力为1 bar和低入口过冷度为5 K的条件下，同时测定局部传热速率和流动可视化。结果表明，随着通道长宽比的增大，换热系数增大，流动沸腾压降减小。然而，在具有最小通道纵横比的散热器中，使用散热器基底面积计算的热传递率较高，这表明由于最大表面积而增强。
The effect of channel aspect ratio on flow boiling characteristics (flow patterns, heat transfer and pressure drop) of HFE-7100 in copper multi-microchannel heat sinks was investigated experimentally. Three heat sinks with base area 500 mm2, channel hydraulic diameter 0.46 mm and channel aspect ratio (ratio of channel width to channel height) of 0.5, 1.0 and 2.0 were tested. The average surface roughness of the channel bottom surface was nearly the same in the three heat sinks and the measured values were 0.271, 0.286 and 0.304 µm. The local heat transfer rates were determined simultaneously with flow visualisation at mass flux ranging from 50 to 250 kg/m2s, wall heat flux from 9.6 to 191.6 kW/m2, system pressure of 1 bar and low inlet sub-cooling of 5 K. The results showed that, when the channel aspect ratio increased, the heat transfer coefficient increased, while the flow boiling pressure drop decreased. However, the heat transfer rate calculated using the heat sink base area was higher in the heat sink with the smallest channel aspect ratio, indicating an enhancement due to the largest surface area.