Comparative numerical study of R134a and low global warming potential refrigerants during condensation inside a smooth and dimpled tube

The present numerical analysis focused on the low-GWP refrigerants during condensation inside a smooth and dimple tube. The low global warming potential refrigerants considered for the present numerical analysis are hydrocarbon includes propane (R290) and propylene (R1270), hydrofluoroolefin includes 2,3,3,3-tetrafluoropropene (R1234yf) and 1,3,3,3-tetrafluoropropene (R1234ze(E)), hydrofluorocarbon 1,1-difluoroethane (R152a), and an azeotropic mixture R430A (R152a 76% + R600a 24% by mass). The working conditions are mass velocity ranges between 50 and 200 kg/m(2)s, dryness fraction of 0.5 and 0.75, heat flux of 5 kW/m(2), and temperature of saturation of 30, 40, and 50 degrees C. The effect of saturation temperature, mass velocity and dryness fraction were investigated along the smooth and dimpled tubes. The VOF model is used to solve the mathematical formulations and the evaporation/condensation rate is determined by using Lee's model. The simulated void fractions were reduced by 2.18% for R134a, 3.93% for R290, 3.31% for R1234yf, 2.55% for R1234ze(E), 3.52% for R1270, 2.42% for R430A, and 1.37% for R152a by increasing the saturation temperature from 30 to 50 degrees C at a quality of 50% inside a smooth tube. And, the two-phase friction factor was reduced by 5.38% and 2.42% with R1234yf at a dryness fraction of 0.5 and saturation temperature of 40 degrees C for smooth and dimple tubes. Also, the pressure drops were increased by increasing the mass flux and decreasing the saturation temperature along the smooth and dimpled tube.