Two-phase heat transfer characteristics of R141bin rectangular micro-channels

An experimental study of two-phase flow heat transfer characteristics in rectangular micro-channels of 1mm and 0.5mm hydraulic diameter was conducted. R141b was used as the working fluid. In this experiment, the heat flux ranged from 1 to 16kW/m2, the mass flow rate ranges from 111.1kg/(m2·s) to 333.3kg/(m2·s), and the mass vapor quality ranged from 0 to 1. In order to know the main factor affecting heat transfer, the relationships of average heat transfer coefficient between heat flux, mass flow rate and mass vapor quality were analyzed. Result showed that, when the heat flux was low, the average heat transfer coefficient decreased as heat flux increase was affected by boiling heat transfer, and the opposite trend came when the mass flow rate became large. Under the condition of low heat flux, the average heat transfer coefficient changed obviously with the mass flow rate, and the mass flow rate had weak effect on the average heat transfer coefficient after the heat flux increased to a certain value. When the mass flow rate ranged from 111.1kg/(m2·s) to 333.3kg/(m2·s), the average heat transfer coefficient decreased as mass vapor quality increased.