Numerical simulation of flow and cooling heat transfer of supercritical pressure refrigerants in chevron-type plate heat exchanger

Abstract

In industrial fields, heat sources exceeding 130°C are necessitated; hence, the development of industrial high-temperature heat pump systems is anticipated. For the heat release process in such heat pump systems, the use of a plate heat exchanger (PHE), in which high-pressure working refrigerant flows, is examined. In this study, to predict the cooling heat transfer coefficient and pressure drop of supercritical pressure refrigerants flowing in a chevron-type PHE, a computational fluid dynamics model is developed. HFC134a and HFO1234ze(E) are selected as the working refrigerants. Calculations are performed by changing the inlet fluid enthalpy under three reduced pressure conditions from 1.01 to 1.21 and two mass flow rate conditions. The heat transfer coefficient and pressure drop obtained from the simulation reproduced the experimental results well, including the effects of pressure and mass velocity. Therefore, the present model can be applied to existing and new refrigerants if their physical properties are available. Furthermore, it can be used to optimize the plate shape of chevron-type PHEs. Finally, based on the simulation results, the characteristics of the flow behavior and heat transfer of refrigerants in the PHE are discussed.