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对以湿蒸汽为工作流体的多喷嘴汽–液喷射器机制进行研究,利用质量、能量及动量守恒方程建立了喷射器工作特性一维理论模型。模型求解过程中,采用两相临界流均相平衡模型计算单喷射蒸汽喷嘴的临界流速,并利用多喷射速度系数对其修正,得到多喷射蒸汽喷嘴的出口速度;综合考虑Cattadori的壁面力和Howard的喉部压损理论对流动的影响来确定混合室阻力。为验证模型的正确性,设计以湿蒸汽为工作蒸汽的实验台,并采用多喷嘴喷射器作为实验元件。研究结果表明:容积喷射系数随压力比的增大而减小,且增大喷射器的截面比可使容积喷射系数增加,但缩小了喷射器的工作范围;容积喷射系数随蒸汽干度的增大和过冷水温度的升高而减小。理论计算结果与实验值基本相符。
A multi-nozzle steam-liquid ejector mechanism using wet steam as the working fluid is studied, and a one-dimensional theoretical model of injector operating characteristics is established by using mass, energy and momentum conservation equations. In the process of model solving, the critical flow velocity of single-jet steam nozzle was calculated by the two-phase critical flow equilibrium model, and the multi-jet velocity coefficient was used to correct the outlet velocity of multi-jet steam nozzle. Considering the wall force of Cattadori and Howard The effects of throat pressure loss theory on flow to determine the mixing chamber resistance. In order to verify the correctness of the model, a wet bench was designed with steam as the working steam, and a multi-nozzle injector was used as the experimental element. The results show that the volume injection coefficient decreases with the increase of pressure ratio, and increasing the injector cross section ratio can increase the volume injection coefficient, but reduces the working range of the injector. The volume injection coefficient increases with the increase of steam dryness Large and cold water temperature decreases. The theoretical calculation results are in good agreement with the experimental ones.