An experimental study of refrigerant distribution in an automotive condenser

Abstract

The literature shows almost no prior investigations on two-phase flow distribution in a parallel flow condenser. In the present study, R-134a flow distribution tests were conducted in the test section, which simulated an actual parallel flow condenser having 58 mini-channel tubes and 4 passes. R-134a gas was supplied at 25 °C superheat, which exited the test section at 5 °C subcooled condition. At inlet of the header, the flow distribution was relatively uniform, except at topmost channels. At the second and third pass, the flow distribution was also relatively uniform except at topmost and bottommost channels. At the exit of each pass, two-phase jets were issued from the tubes of the previous pass, which hit opposite wall of the header, and flowed downward forming a liquid film. At the bottom of the header, the remnant liquid, which was not supplied into the next pass, formed a liquid pool. The thermal degradation due to flow mal-distribution was not significant (0.1–2.82%), which increased as mass flux decreased. Flow distribution correlations were developed to predict the fraction of liquid or gas taken off by downstream channel as a function of gas Reynolds number and channel inlet vapor quality.