A Two‐Phase Pressure Drop Model fo rHomogenous Separated Flowfor Circular Tube Condenser, Examined with Four Modern Refrigerants

Abstract

This study presents an analytical model for the calculation of two‐phase pressure drops for homogeneous separated flow for circular tube condensers. Four different refrigerants were used to examine the pressure‐drop model, and some parameters were selected for a trial test, such as vapor quality, inner tube diameter, and the mass flux at a given saturated temperature. The model demonstrates strong validity compared to previous works. The saturated temperature is given at 40oC because most average condensing temperatures are equal to, or are approaching, this value. The pressure‐drop model was examined with four refrigerants: R134a, R507A, R600a, and R1234xyh. These refrigerants had different critical pressures, critical temperatures, and molecular weights. Three inner tube diameters were used to examine the model at 6mm, 8mm, and 12mm, and the mass flux was 100, 200, 300, 500, and 800 kg/sec. m2, with vapour quality ranging from 0.1 to 0.9 to 0.1 steps. The results indicate a good agreement of the two‐phase pressure‐drop behaviour for completely variable parameters compared with previous works. Finally, these findings suggest that this model can contribute to the design of heat exchangers and/or condensation tubes for other refrigerants.