喷射制冷系统中两级喷射器性能的 CFD 模拟研究

两级喷射器是一种可以利用混合室内耗散的动量来提升其性能的装置,相较于传统的单级喷射器其喷射系数显著提高,但目前对两级喷射器在制冷系统中的研究有限。文章提出一种新的可用于制冷系统中的两级喷射器,并采用计算流体动力学(computational fluid dynamics, CFD)对两级喷射器的性能进行研究。采用 $ k-\omega $ SST湍流模型、R134a制冷剂对不同工作压力、引射压力、冷凝压力下的两级喷射器进行模拟,并与同工况条件下单级喷射器的性能进行对比。研究结果表明,与单级喷射器相比,两级喷射器的喷射系数最高可提高57.50%,而临界冷凝压力有所下降,最大可降低18.98%。

The two-stage ejector (TSE), as a device with the enhanced performance by taking full advantage of the dissipated momentum in the mixing chamber, has significantly improved the entrainment ratio compared to the traditional single-stage ejector (SSE). However, limited research has been focused on the TSE in refrigeration system. Herein, a new TSE used in the refrigeration system was studied, as well as its performance according to computational fluid dynamics (CFD). Meanwhile, the $ k-\omega $ SST turbulence model and R134a refrigerant were adopted, the performance of TSE under different working pressure, injection pressure and condensing pressure was simulated and compared with that of the SSE under the same working condition. The results show that compared with the SSE, the entrainment ratio of the TSE increases up to 57.50%, whereas the critical condensing pressure may reduce by 18.98% or less.