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比较了CAVALLINI的纯质和混合工质水平内螺纹管中流动沸腾换热系数的关联式,结果显示在内螺纹管中,对近共沸混合工质R404A的沸腾换热系数进行工程计算时,R404A被看作纯质和混合工质计算所得的沸腾换热系数值差别最大不到10%,因此可将其以纯质对待;对CAVALLINI的纯质和混合工质、KOYAMA及THOME等四个水平内螺纹管流动沸腾换热系数的影响因素进行对比分析,结果表明R404A的沸腾换热中对流沸腾换热占主导地位,且随干度增加而增加。对关联式的理论预测和实验结果进行对比,表明CAVALLINI和THOME关联式的预测误差小于21%,因此它们对R404A适用性较好,这对R404A蒸发器的工程设计及优化具有一定参考意义。
The correlation between the boiling heat transfer coefficient of CAVALLINI and that of mixed refrigerant in horizontal screw tube was compared. The results show that when the boiling heat transfer coefficient of near-azeotropic refrigerant R404A is calculated in the female screw tube, R404A is considered as pure and mixed working fluid calculated boiling heat transfer coefficient difference of less than 10% maximum, so it can be treated as pure; CAVALLINI pure and mixed refrigerant, KOYAMA and THOME four levels The results showed that the convective boiling heat transfer dominated the boiling heat transfer in R404A, and increased with the increase of dryness. The correlation between the theoretical prediction and experimental results show that the prediction error of CAVALLINI and THOME correlation is less than 21%, so they have good applicability to R404A, which is of certain reference significance for engineering design and optimization of R404A evaporator.