| 摘要: |
| 针对R404A的冷凝传热与压降关联式不少，但都是基于7 mm或者9.52 mm等大管径光管或者强化管，针对5 mm管径的关联式也都是适用于其它制冷剂，没有R404A小管径冷凝直接适用的关联式。本文通过实验测试与理论计算结合论证的办法，利用控制变量法、性质相似制冷剂优先法筛选出一批关联式，大量对比由关联式计算与由实验数据计算得出的传热系数与压降的偏差，研究关联式的适用性及可修正性。结果表明：Dobson and Chato冷凝换热关联式乘以修正系数2.13，能很好预测R404A在内螺纹管中的冷凝传热系数，与实验值正偏差为+15.51%，负偏差为﹣14.13%。黄翔超提出的摩擦压降关联式能很好预测R404A在小管径内螺纹管内冷凝的摩擦压降，与实验值的正偏差为+12.56%，负偏差为﹣13.58%，两者均可为换热器设计计算提供较准确的理论指导。 |
| 关键词: 关联式 小管径 冷凝 传热系数 压降 R404A |
| DOI： |
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| 基金项目:上海市教育委员会重点学科资助项目(J50502)资助。 |
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| Suitability of R404A Condensation Heat Transfer and Pressure Drop Correlations for Small Diameter Tube |
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Wang Xuedong1, Liu Jianhua1, Song Ji2, Gao Yifeng2, Zhu Lijun1
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| (1.School of Energy and Power Engineering, University of Shanghai for Science and Technology;2.International Copper Association Shanghai Office) |
| Abstract: |
| Many correlations have been proposed about R404A condensation heat transfer and pressure drop, but all of them apply for smooth tubes or microfin tubes with big diameter. Some correlations are based on 5 mm diameter tube, but the refrigerant is not R404A. Up to now, there is no correlation for R404A condensation heat transfer and pressure drop with 5 mm diameter tube. In this paper, a number of correlations were selected by variable-controlling and giving priority to refrigerant with similar properties, combining experimental test and theoretical calculation, deviation between the calculated and experimentally measured values have been compared through a large amount of data to demonstrate the applicability and revisability of the correlations. The research results indicate that modified Dobson and Chato condensation heat transfer correlation (multiplied by the correction factor 2.13) shows good predictability of condensation heat transfer coefficient of R404A in small diameter microfin tube within a deviation of ﹣14.13% to +15.51%. The friction pressure drop correlation proposed by Huang Xiangchao can well predict the friction pressure drop of R404A in small diameter microfin tube within a deviation of ﹣13.58% to +12.56%. Both correlations can provide more accurate theoretical guidance for the calculation and design of heat exchanger. |
| Key words: correlations small diameter tube condensation heat transfer coefficient pressure drop R404A |
