蒸汽喷射压缩器的变工况特性分析

蒸汽喷射压缩器工作特性对系统性能产生很大的影响。文中采用气体动力函数法,建立了蒸汽喷射压缩器变工况特性数值计算模型,对热压缩海水淡化系统中的蒸汽喷射压缩器的变工况性能进行了计算,分析了工作蒸汽压力、引射压力、混合蒸汽压力对喷射系数的影响。计算结果表明,当压缩蒸汽的压力低于一定值时,喷射系数保持不变;喷射压缩器特性对蒸发压力的变化最为敏感,引射压力的微小变化将导致喷射器性能的明显变化;而提高工作蒸汽压力,在一定范围内可以提高喷射器的性能,但超过一定数值后反而会引起喷射器性能的降低。与试验结果对比表明,采用该方法能够正确地预测喷射压缩器的工作性能。

Performance simulation and analysis of steam ejector under different operating condition

Steam ejector working characteristic has great impact on the system performance.Computational model of steam ejector was set up by introducing gas flow dynamic function,and the performance under different operating condition was studied for the steam ejector applied in thermal vapor compression desalination plant.The effects of entrainment ratio on motive steam pressure,suction pressure,compression vapor pressure were calculated and analyzed.The results of the simulation indicate that the entrainment ratio can be maintained at a constant value when the compression vapor pressure is under a certain value.The steam ejector performance is very sensitive to the change of suction pressure.A minor change of the suction pressure can lead to a drastic change on the steam ejector operating performance.The increase of the motive steam pressure can slightly improve the performance of the steam ejector under a certain range,but will lower the performance beyond this range.By matching the test data with the simulation results,it shows that the simulation model can accurately predict the performance of the ejector.