R404A小管径冷凝换热与压降关联式的适配性

发布时间：2019-04-24 01:10

【摘要】：针对R404A的冷凝换热与压降关联式有很多,但均为基于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。本文采用实验测试与理论计算结合论证的方法,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换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:M.K.Dobson等提出的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换热系数,与实验值正偏差为+15.51%,负偏差为-14.13%。X.C.Huang等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。
[Abstract]:There are many correlations between condensation heat transfer and pressure drop for R404A, but all of them are based on 7 mm or 9.52 mm large diameter optical tubes or reinforced tubes. The correlations for 5 mm pipe diameters are also suitable for other refrigerants. There is no correlation for direct application of R404A tube diameter condensation. In this paper, a series of correlations are selected by means of experimental test and theoretical calculation, by means of control variable method and similar refrigerant priority method. The deviation between the heat transfer coefficient and the pressure drop calculated from the correlation and the experimental data is compared in a large amount, and the applicability and correction of the correlation are studied. The results show that the condensation heat transfer coefficient in R404A tube can be well predicted by multiplying the condensation heat transfer correlation proposed by M.K.Dobson et al by the correction coefficient 2.13, and the positive deviation from the experimental value is 15.51%. The correlation of friction pressure drop proposed by-14.13%.X.C.Huang et al can predict the friction pressure drop of R404A in the inner thread tube of small tube diameter. The positive deviation is 12.56% and the negative deviation is-13.58% with the experimental value, and the negative deviation is-13.58%, the negative deviation is-13.58%. Both of them can provide more accurate theoretical guidance for the design and calculation of heat exchangers.
【作者单位】：上海理工大学能源与动力工程学院;国际铜业协会(中国);
【基金】：上海市教育委员会重点学科资助项目(J50502)资助~~
【分类号】：TB657.2

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