Numerical Simulation And Structural Optimization Of Ejector In Solar Ejector Refrigeration System

Because of low operating cost and small geographical limit,solar air-conditioning has become the focus of many researchers.Many countries in the world are carrying out research on low-grade heat source driven air-conditioning technology,such as waste heat utilization air-conditioning,solar air-conditioning and so on.Jet refrigeration system shows the advantages of simplicity,stable operation,high reliability and simple maintenance,siutable for the low-grade energy recovery.The solar energy used in the heat source of the jet refrigeration has become important projects of the researchers.As one of the most important components of the jet refrigeration system,the performance of the injector affects the system performance directly.Therefore,it is important to increase the working efficiency of the jet refrigeration system.The main work of this paper includes:(1)Analyzing the working principle of the injector and design the geometry size of the injector according to the actual working conditions.The geometric parameters of the injector was determined by using the gas dynamic method.The influences of different factors on the flow characteristics are investigated in detail.The optimal structure of the injector can make the internal flow more evenly and reduce the internal pressure loss due to the shock effect.(2)The injector structure is simplified as a two-dimensional model.The grid model is generated by the ICEM pretreatment software.The Fluent numerical simulation software is used to calculating the flow,temperature and pressure distribution of the flow field in the injector.(3)Under different conditions,the injector performance was calculated.It is found that the injection coefficient decreases with the increase of the working pressure and increases with the increase of the pressure of the ejection fluid.The injection coefficient keeps unchanged as the outlet pressure changes within a certain range.However,the injection coefficient drops sharply as the outlet pressure exceeds a critical value.(4)By Fluent numerical simulation,the influence of structure parameters on theinjector performance was calculated,including the nozzle distance,mixing chamber diameter ratio,nozzle exit and mixing chamber diameter ratio and nozzle throat diameter.The structure parameters,such as the nozzle distance,mixed ratio for and nozzle exit and mixing chamber diameter ratio and nozzle throat diameter,are optimized.Less than or greater than the optimum parameters will results in the deterioration of the injector's performance.(5)Through the cone in the center of the ejector back to increase control injector throat area,By the numerical analysis for the adjustable ejector at different opening,it is found that,with the decrease of the opening,the shock mode inside the injector will change gradually and lead to different flow resistance loss.The optimum value of throat opening will induce lowest pressure loss in the injector,thus inproving the performance of injector.(6)Design the experimental platform of solar jet refrigeration system and conduct experimental research.