Experimental investigation in nucleate pool boiling of binary refrigerant mixtures

Heat transfer coefficients in nucleate pool boiling for refrigerants under saturated conditions at 0.9 MPa were measured on a horizontal copper surface. Those refrigerants were the pure components of HFC-134a, HFC-32, HFC-125 and two kinds of binary mixtures: nonazeotrope mixture HFC-32/134a, azeotrope mixture HFC-32/125 compared to pure components, both binary mixtures showed lower heat transfer coefficients. This deterioration was more pronounced as heat flux was increased. Experimental data were compared with some empirical and semi-empirical correlations available in literature. For binary mixtures, the accuracy of those correlations varied considerably with mixtures and heat flux.