A Simulation for the Flow Distribution and Unsteady Behavior of Flow Boiling in Parallel Mini-Channels

Abstract

A novel heat exchanger using parallel small refrigerant channels has recently been developed to improve the performance of air conditioning systems. However, for boiling flow in parallel channels, accurate prediction of heat transfer capacity is not easy because mass flow rates in respective channels tend to be non-uniform among them and/or oscillate. The authors have developed a simulation model which predicts the heat transfer capacity including the cases of non-uniformly distributed and oscillatory flows. In this paper, to confirm the validity of this model, the simulation for oscillatory flow occurred in parallel two mini-channels was compared with experiment. The simulation reproduced well the oscillatory flow characteristics obtained by the experiment. Additionally, the simulation predicted inlet flow rates and outlet qualities of respective channels in the parallel two channels under non-uniform heat flux condition.