Gas-Liquid Flow Distribution in Multi-Pass Upward Channels

Abstract

The gas-liquid flow distributions in the multi-pass upward channels that simulated the compact evaporators for the automobile air-conditioning system were investigated experimentally. Special attention was directed to influences of the inlet flow pattern at the header entrance, pressure condition at the branch outlets, and pressure-loss characteristics of branches on the gas-liquid distributions. Experiments were conducted in an isothermal air-water flow system. It was found that the pressure condition at the branch outlets exerted a great influence on the gas-liquid distributions to branches when flat smooth tubes were adopted as branches, but it had a minor influence when the branches consisted of multi-port tubes. The inlet flow pattern at the header entrance had a significant influence on the gas-liquid distribution, and liquid tended to be distributed to all the branches when the inlet flow pattern is a mist flow.