CFD Analysis On Performance Of Steam Ejector And Its Application In Saving Energy Technology

As a fluid equipment, steam ejector can improve pressure of fluid without mechanical energy and its structure is simple and reliable. Until now the design and evaluation of an ejector are usually based on 1-D analysis for complex flowing and mixing process. There is a limitation on mastering the effects of geometric parameters of an ejector on its entrainment ratio, so it is difficult to improve the Coefficient of Performance of an ejector. In virtue of FLUENT software, simulation of steam ejector was carried out. Through analysis of the simulation results, many relations between ejector COP and operating and structural parameters were mastered. Steam ejector was applied in evaporation and concentration system, so heat pump evaporation and concentration system which can save energy was brought forward. Experiments were made with heat pump evaporation system and self-cycle evaporation system. The main work and results of this paper are given as follows:(1) A CFD mathematic model which was suitable for ejector numerical simulation was set up and the compressible flow process in a steam ejector was simulated on the basis of Reynolds-Averaged equations, turbulence viscosity model and gas state equation. The results of simulation and experiments were compared and the CFD mathematic models which can simulate performance of ejector were determined.(2) Relationships between the ejector performance and its operating parameters systematically were summarized. From the results of simulation, it was concluded how the motive fluid pressure, the suction fluid pressure and the discharging fluid pressure influence performance of steam ejector. One parameter named expansion ratio was introduced and the chart of the relations between expansion ratio and the maximum entrainment ration was given. The relative conclusion can be used to analyze a given ejector parameter characteristics in order to correctly apply and operate it.(3) Effect of ejector structures on performance was analyzed. Through simulating...