An Experimental Investigation of Convective Boiling Heat Transfer Using Alternative and Natural Refrigerants Inside Horizontal Microchannels

In present study, the two phase flow boiling heat transfer coefficient and pressure drop of R32 , R410A and R290 in microchannels are demonstrated. The experimental data were conducted in horizontal stainless steel tubes with the inner diameter of 0.3 mm and 1.5 mm. The testing conditions were performed with the mass fluxes range from 200 to 500 kg/m2s, the heat fluxes from 5 to 15 kW/m2, the saturation temperature of 5 and 10˚C and the vapor quality from 0.1 to dry-out. The effects of mass flux, heat flux and saturation temperature on the heat transfer coefficient and pressure drop were analyzed. The experimental data were also compared with some well-known heat transfer coefficient and pressure drop correlations. A modified heat transfer coefficient correlation for alternative and natural refrigerants was proposed and predicted well the present experimental data