Condensation heat transfer and pressure drop in flattened microfin tubes having different aspect ratios
Condensation heat transfer and pressure drop in flattened microfin tubes having different aspect ratios
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DOI：
10.1016/j.ijrefrig.2013.09.035
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发表时间：
2014-02
期刊：
影响因子：
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通讯作者：
Eul-Jong Lee;Nae-Hyun Kim;H. Byun
中科院分区：
文献类型：
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作者：
Eul-Jong Lee;Nae-Hyun Kim;H. Byun
在本研究中，获得了R-410 A在外径为7.0 mm的扁平微肋管内的凝结换热系数和压降。圆形微翅管测试范围包括饱和温度45 °C，质量通量100-400 kg m−2s− 1和质量0.2-0.8。结果表明，高宽比对凝结换热系数的影响与流型有关。对于环状流，传热系数随着纵横比的增加而增加。然而，对于分层流，传热系数随着纵横比的增加而减小。压降总是随着纵横比的增加而增加。可能的推理的基础上，提供了估计的流动模式在扁平微翅管。与现有的圆形微肋管的关联式进行了比较。
In this study, condensation heat transfer coefficients and pressure drops of R-410A are obtained in flattened microfin tubes made from 7.0 mm O.D. round microfin tubes. The test range covers saturation temperature 45 °C, mass flux 100–400 kg m−2s−1and quality 0.2–0.8. Results show that the effect of aspect ratio on condensation heat transfer coefficient is dependent on the flow pattern. For annular flow, the heat transfer coefficient increases as aspect ratio increases. For stratified flow, however, the heat transfer coefficient decreases as aspect ratio increases. The pressure drop always increases as aspect ratio increases. Possible reasoning is provided based on the estimated flow pattern in flat microfin tubes. Comparison with existing round microfin tube correlations is made.