Flow distribution of two-phase refrigerant in plate heat exchangers.

The present study provides experimental observations of air-water and two-phase refrigerant in plate heat exchangers with inlet distributors. A transparent Pyrex plate heat exchanger was used for air-water flow visualization and the Infrared Thermography was used for measuring the surface temperature of a plate heat exchanger with two-phase refrigerant heat transfer inside. The heat transfer performance experiment results and numerical analysis results for air-water flow by Yang et al. (2012) were included for comparison. The air-water mixture flow visualization results show that the effect of Reynolds number on the flow distribution is not high. Flow in the plate with the distributor in the direction 6 provided the most uniform distribution at both high and low Reynolds number conditions. The Infrared thermal images show that the temperature distribution at the cross section of midways along the bulk flow of refrigerant for the plate with distributor in direction 12 are the least in comparing to plates with distributor in other directions. The results of overall heat transfer coefficient test also show that the most uniform refrigerant flow resulted in the highest overall heat transfer performance.