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建立氨水液-汽型喷射器的一维稳态热力学模型,对喷射器的热力学性能与结构进行研究,包括工作喷嘴、扩散段中的工作流体与引射流体的压力及速度的变化,以及不同扩散角对喷射器性能的影响。将氨水液-汽型喷射器应用于Kalina循环,以降低膨胀机的背压来提高循环输出功与效率。在对喷射器性能,如:引射系数、引射压力及混合出口压力等相互关系分析基础上,以得到Kalina循环更高的循环输出功为目的,对喷射器的性能与结构进行研究。结果表明,喷射器的扩散角越小,越有利于喷射器的压力回收,扩散角越大,越有利于汽、液两相的混合。给定喷射器混合出口压力时,引射系数越小,引射压力越小。引射系数对提高Kalina循环性能起关键作用。最终优化得到的喷射器设计工况为:扩散角为1°、引射系数0.1、引射压力656 k Pa。
The one-dimensional steady-state thermodynamic model of ammonia-liquid ejector was established to study the thermodynamic performance and structure of the ejector, including the variation of pressure and velocity of working fluid and ejecting fluid in the working nozzle, diffusion section, Effect of Diffusion Angle on Ejector Performance. Ammonia liquid-vapor injectors are used in the Kalina cycle to reduce the backpressure of the expander to improve cycle output and efficiency. Based on the analysis of the relationship between injector performance, such as injection coefficient, injection pressure and mixed outlet pressure, the performance and structure of the injector were studied in order to obtain higher circulating output power of Kalina cycle. The results show that the smaller the diffusion angle of the injector, the more beneficial to the pressure recovery of the injector. The larger the diffusion angle is, the better the mixture of the two phases is. Given an ejector mixing outlet pressure, the smaller the ejector coefficient, the smaller the ejector pressure. Emissivity plays a key role in improving Kalina cycle performance. The optimized ejector design conditions are: diffusion angle of 1 °, ejection coefficient of 0.1, and injection pressure of 656 kPa.