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合成气压缩机循环段由于高压和流动空间限制,难以测量内部流动参数,导致无法从工程上判断循环段流动性能。为此本文建立了高压缸出口段、混合腔和循环段叶轮流道模型,采用合成气物性,在约14.4 MPa（A）的高压进口条件下,使用CFD的方法研究了循环段内部流动混合发展规律。选取常用的七种损失模型评估了叶轮内损失,并研究了混合腔对下游叶轮性能的影响。结果表明混合腔内呈现出明显的二次流动,随着流动向下游发展,流场变得越来越均匀。混合腔损失、叶片负载损失和尾迹损失是主要的损失源。由于上游混合腔的影响,带有混合腔的叶轮的压比和效率低均低于单独均匀进口叶轮情况,且其工况范围更窄。本文的结果可为新型合成气压缩机产品的设计提供参考。

Restricted by high operating pressure and flow domain, it is difficult to test mixing performance of internal flow field of recycle section in the syngas compressor. A flow model was established including the outlet part of the high pressure section, mixing chamber and recycle stage impeller. The flow field in the recycle section was numerically investigated based on CFD under inlet pressure of 14.4 MPa with real gas model. Seven loss mechanisms were evaluated for the mixing performance of the recycle section. Obvious secondary flow phenomenon was detected in the mixing chamber. With the development of the flow, the flow field became more and more uniform. Mixing chamber loss, blade loading loss and wake loss were found to be the main loss sources. Influenced by the upstream flow, the efficiency and pressure ratio of the mixing flow was smaller than that with uniform inlet condition, and the operating range was narrower. The paper was presented to assist the understanding of internal flow fields in the mixing chamber and serve as a guideline for improving design of next compressor product.