In order to maximize the working potential of a steam ejector, aside from experiment testing of various design parameters, it is also important to understand the involved thermal fluid mixing behaviors. In this study, an ejector refrigeration experimental system was established, and a numerical model was developed to comprehend the complex and non-linear flow characteristic using an ideal gas model which is more consistent with the experimental data compared with the wet steam model. Herein, it was discovered that the choking flow and the occurrence locations of this phenomenon played an essential role in the system efficiency. For the first time, three choke behaviors modes were characterized by means of numerical investigations: “fit-choked flow mode”, “sub-choked flow mode” and “super-choked flow mode”. The relationship between the choke and the normal shock wave was revealed to analyze the two mixing fluids flow conditions. The influence of primary fluid pressure and the back pressure on the ejector performance under three choke flow modes were comprehensively discussed. The simulation results indicated that the choking flow was a critical factor in affecting the performance of the steam ejector, and the performance optimizes at “fit-choked flow mode” when the primary fluid pressure was 0.36 MPa with a remarkable entrainment ratio of 0.525.

为了最大程度地发挥蒸汽喷射器的工作潜力，除了对各种设计参数进行实验测试外，了解所涉及的热流体混合行为也很重要。在这项研究中，建立了喷射器制冷实验系统，并建立了一个数值模型以使用理想气体模型来理解复杂和非线性的流动特性，该模型与湿蒸汽模型相比更符合实验数据。在此，发现该现象的阻塞流和发生位置在系统效率中起着至关重要的作用。首次通过数值研究表征了三种节流行为模式：“节流模式”，“次节流模式”和“超级节流模式”。揭示了扼流圈与正常冲击波之间的关系，以分析两种混合流体的流动条件。全面讨论了三种节流模式下一次流体压力和背压对喷射器性能的影响。仿真结果表明，节流是影响蒸汽喷射器性能的关键因素，当主流体压力为0.36 MPa，夹带比为0.525时，性能在“节流模式”下达到最佳。