Evaporation Heat Transfer and Pressure Drop of Refrigerant R-410A Flow in a Vertical Plate Heat Exchanger

摘要

Experiments are carried out here to measure the evaporation heat transfer coefficient h_r and associated frictional pressure drop ΔP_f in a vertical plate heat exchanger for refrigerant R-410A. The heat exchanger consists of two vertical counterflow channels which are formed by three plates whose surface corrugations have a sine shape and a chevron angle of 60 deg. Upflow boiling of refrigerant R-410A receives heat from the hot downflow of water. In the experiments, the mean vapor quality in the refrigerant channel is varied from 0.10 to 0.80, the mass flux from 50 to 100 kg/m~2s, and the imposed heat flux from 10 to 20 kW/m~2 for the system pressure fixed at 1.08 and 1.25 MPa. The measured data indicate that both h_r and ΔP_r increase with the refrigerant mass flux except at low vapor quality. In addition, raising the imposed heat flux is found to significantly improve h_r for the entire range of the mean vapor quality. However, the corresponding friction factor f_(tp) is insensitive to the imposed heat flux and refrigerant pressure. Based on the present data, empirical correlations are provided for h_r and f_(tp), for R-410A in the plate heat exchanger.