Numerical and experimental investigation of heat and mass transfer performance of pool boiling type shell and plate evaporator

Abstract

Computational fluid dynamics is critical for promoting understanding of evaporation heat transfer in chevron plate heat exchangers. In this study, the volume of fluid method is employed in the FLUENT code to solve two-phase flow. The Lee model is employed to simulate the phase change of the refrigerant R134-a. Validation is performed by comparing the predicted heat transfer coefficient and experimental data. The effects of surface roughness, saturation temperature (Ts) of the refrigerant, heat flux, and spacing between the plates (S) on the heat transfer coefficient and flow field are studied. The predicted and experimental results indicate that surface roughness has a significant effect on the heat transfer coefficient, nucleation site density, and size of the detached bubbles. The value of S of the evaporator was varied (S = 17, 12, and 7 mm) to predict the optimal heat transfer performance. The predicted results show that at S = 12 mm, the plate heat exchanger exhibits good performance. The saturation temperature of R-134a exhibits a considerable effect on heat transfer coefficient when Ts increased from 4.4 to 7°C, but shows no effect on increasing Ts to 10°C.