FLOW BOILING HEAT TRANSFER OF TERNARY MIXTURE IN A MICRO-CHANNEL

This paper describes the flow boiling heat transfer of R123/R134a/R22 mixture in a single round micro-channel with 0.19 mm ID. The flow boiling heat transfer coefficients were measured for ternary mixture (R123/R134a/R22 mole fraction: 0.194/0.62/0.186) at various experimental conditions: mass velocities (314, 392, 470 kg/m(2)-s), heat fluxes (10, 15, 20 kW/m(2)) and vapor qualities (0.2 - 0.8). The heat transfer characteristics of the R123/R134a/R22 mixture are similar to those of the R123/R134a mixture (mole fraction: 0.502/0.498) observed in the previous flow boiling experiment which indicates that major heat transfer mechanism in the micro-channel is dominated by evaporation of thin liquid film around the elongated bubbles. The large reduction of heat transfer coefficients compared with pure refrigerant is observed in micro-channel flow boiling by mass transfer effect of mixed refrigerant.