R290与R404A在水平管内沸腾换热的压降研究

In-tube Evaporation Pressure-drop Characteristics of R290 and R404A

将R22的两种新型替代工质R290和R404A在光管和内螺纹管中的沸腾换热压降实验结果与Lockhart&Martinelli压降计算关联式预测结果进行了比较,并依据工质R290和R404A在内螺纹管中的实验压降值对Lockhart&Martinelli压降计算关联式进行了修正。结果表明Lockhart&Martinelli关联式对R404A在光管和内螺纹管的沸腾换热摩擦压降,均有良好的预测精度,平均偏差分别为-11.52%和-17.86%。Lockhart&Martinelli关联式可以较好的预测R290在光管内的沸腾换热摩擦压降,平均偏差为-21.68%;经修正后的Lockhart&Martinelli关联式可以较好的预测R290在在内螺纹管中的沸腾换热摩擦压降,Lockhart&Martinelli关联式乘上修正系数2.06后的修正值与实验值偏差较小,平均偏差为2.37%。研究结果对R290和R404A蒸发器的工程设计及优化具有一定参考意义。

The experimental results of in- tube evaporation pressure- drop of R290 and R404A in the horizontal smooth tube and the horizontal microfin tube were compared with calculation results by Lockhart ＆ Martinelli pressure - drop correlation, respectively. Moreover, based on the experimental data of R290 and R404A, Lockhart ＆ Martinelli pressure - drop correlation was modified adequately. For R404A. the correlation shows good agreement with experimental values with mean deviation of - 11.52% for the smooth tube and - 17.86% for the microfin tube. Lockhart ＆ Martinelli pressure drop correlation can also predict well the in - tube evaporation pressure- drop of R290 for the smooth tube with mean deviation of -21.68%. However, 2.06 to agree well with the experimented data should multiply the predicted value for the microfin tube by Locldlart ＆ Martinelli correlation, and the mean deviation is 2.37%.