非清洁水冷热源换热管内振荡流动与换热的数值模拟与实验研究.pdfVIP

Abstract The development and utilization of low-grade renewable clean energy have broad prospects. It is an inevitable trend for the sustainable development of energy, buildings and environment. Sewage-source heat pump system can use the low-grade thermal energy in the waste water to provide heating , air conditioning for buildings and provide domestic hot water, with high efficiency and energy saving and significant features of environmental friend. But the waste water contains all kinds of debris. In the heat transfer process the debris would forming fouling resistance and lead to the dropping of the heat transfer efficiency of the system. The aim of this paper is to make a numerical simulation and experimental study of the oscillation flow and heat transfer of the heat pump heat exchanger, and then present a new online anti-fouling technology for the heat pump heat exchanger to improve the heat transfer performance of the system. At first, the physical and mathematical model of turbulence oscillation flow and heat transfer in a tube was established, and then a numerical simulation of turbulent pulsating flow and heat transfer was carried on. The turbulent flow conditions, the wall average convective heat transfer coefficient and the wall shear stress among the heat transfer process were analyzed using CFD software. The influence of the fluid inlet velocity, oscillatiing amplitude and frequency on the wall average convective heat transfer coefficient and wall shear stress was studied. It is shown that when the fluid is Newtonian fluid, the oscillatory flow in circular tube had no effect on turbulent heat transfer. B