Numerical analysis of the flow parameters on the heat transfer performance of a two-stage spiral casing heat exchanger

Abstract

The study of the performance of high-efficiency heat pump systems has been a hot issue of general interest in the field of heat pump air conditioning. For the designed and developed two-stage casing tandem heat exchanger of heat pump system, the 3D finite volume method and the realizable k-ε model are used to numerically analyze the influence law of inlet fluid temperature and flow velocity on the overall heat transfer coefficient as well as the Nussle number of inner and outer tubes. The results show that decreasing the inlet water temperature or increasing the inlet refrigerant temperature can improve the overall heat transfer performance; Nuin increases with the increase of water and refrigerant flow rates, while Nuout increases with the increase of water flow rate but decreases with the increase of refrigerant flow rate; Nuin and Nuout both increase with the decrease of water temperature or refrigerant temperature increases.