Abstract: Experiments are conducted to investigate the flow boiling heat transfer characteristics of refrigerant mixture of R32 and R134a in microchannel tube and mini-channel tubes. The results show that the mass quality and mass flux have nearly no effects on the flow boiling heat transfer, but the heat flux affectes the flow boiling heat transfer greatly, results also show that nucleation boiling heat transfer dominates over most of the heat flux range. Compared with the mini-scale tube, flow boiling heat transfer in microchannel tube is an effective method of achieving high heat transfer coefficient.

Key words: Flow boiling, Microchannel, Non-azeotropic refrigerant mixture