An Experimental Study of Condensation of Nonazeotropic Refrigerant Mixtures HCFC22+CFC114 inside a Horizontal Smooth Tube

An experimental study of condensation of nonazeotiopic refrigerant mixtures (NARMs) of HCFC22 and CFC114 inside a horizontal smooth tube has been carried ont. The local Nusselt number of pure refrigerants of HCFC22 and CFC114 is correlated well with the equation obtained by modifying a semi-empirical equation of Nozu et al., while that of NARMs is lower than the value predicted from the correlation equation, and the magnitude of its decrease depends on the mass velocity and the composition of NARMs. By assuming that the condensate heat transfer coefficient of NARMs can be expressed by the correlation equation for pure refrigerants, temperature and mass fractions of vapor and liquid at the vapor-liquid interface are evaluated, and a correlation equation of the local vapor mass transfer coefficient is obtained. The combination of the correlation equations for condensate heat transfer and vapor mass transfer can accurately predict the heat transfer characteristics of NARMs in a double-tube counterflow condenser.