冷媒の水平平滑蒸発管内熱伝達係数の予測式の修正

抄録

The authors had previously proposed a prediction method of the local heat transfer coefficient for pure refrigerants flowing in horizontal smooth evaporator tubes. This method was compared with new experimental data, and found not to be accurately applicable to refrigerants of a large vapor density and/or flow in a tube of small diameter, particularly in the separated flow regime1nthis prediction method, the separation angle is a primary factor, and correlation of this angle is used not only to classify the flow regime into the annular flow and the separated flow, but also to determine the ratio of the wet perimeter to the whole perimeter f the tube for the separated flow. Based on the new experimental data of the separation angle obtained for refrigerants of a large vapor density and in a small diameter tube, the correlation for the separation angle was reformed so that the predicted heat transfer coefficient agrees well also with the new experimental values.