The Design And Simulation Of An Ejector Used In CO₂Heat Pump Water Heater

With the increasing awareness of environmental protection, CFCS which used in refrigeration and air conditioning were restricted and prohibited, Using natural refrigerant has became a trend. The natural refrigerant CO2, in addition to the environmental significance, while CO2heat pump water heater has its unique advantages compared to the other water heaters. But thermal problem has been became a bottleneck that restricting the development of CO2heat pump water heater. It is a good way to solve this problem which an ejector instead of a throttle, and can prove the system performance.This paper mainly aimed at design a high efficiency and appropriate ejector based on the simulation design for an ejector of CO2heat pump water heater. A simulated program was designed for the ejector with gas dynamics, the theory of the Sokolov’s ejector design and the empirical formula by Visual Basic6.0. And it was used to calculate the size of the ejector of CO2heat pump water heater. The program was also used to analysis the effect of the pressure of working fluid, second fluid and compressed fluid influence to the entrainment ration, and it was studied that the relationship between structure size and working parameters, the throat area and the working fluid flow and the outlet flow of compressed fluid.As a simple one-dimensional analysis cannot gives its internal flow field. simulated ejector which use CO2as the refrigeration, acquired the distribution of pressure, velocity with the fluent software. With the calculation of the simulate software, some variation laws of the fluid flow were acquired under different working parameters, such as the fluid flow, the internal flow field of pressure and velocity, and the entrainment ration, and investigated the effect of the important geometric parameter of the ejector on the ejector performance.