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针对大型内压缩流程,研制出了一台低温液体膨胀机用于替代高压液体节流阀,降低空分系统能耗。液体膨胀机内流会诱发转子振动,影响运行安全。本文将多相流模型与气泡动力学Rayleigh-Plesset模型相结合,研究了液体膨胀机空化特性。首先模拟了低温液氮水翼流动,利用实验数据验证了空化模型和数值方法。进一步将蜗壳、可调喷嘴、叶轮以及扩压管作为整体建模,研究了液体膨胀机两相气化的演变机理,探明了设计流量和非设计流量下膨胀机空化特性。
For the large-scale internal compression process, a cryogenic liquid expander was developed to replace the high-pressure liquid throttle and reduce the energy consumption of the air separation system. Liquid expander flow will induce rotor vibration, affecting operational safety. In this paper, the multiphase flow model and the bubble dynamics Rayleigh-Plesset model are combined to study the liquid expander cavitation characteristics. First, the flow of liquid nitrogen-liquid hydrofoil was simulated and the cavitation model and numerical method were verified by experimental data. Furthermore, the volute, adjustable nozzle, impeller and diffuser were modeled as a whole. The evolution mechanism of two-phase gasification of liquid expander was studied. The cavitation characteristics of expander with designed flow and non-designed flow were proved.