Abstract Cold compressors are the core components needed for the development of a facility for large-capacity refrigeration at superfluid helium temperature. The compressor impeller operates at extremely low temperature and low pressure which involves a performance penalty due to heat transfer from the warm side of the machine to the cold side and thus affects the recycle of the cold exergy downstream. To investigate the heat transfer effect on cold compressor performance, a conjugate heat transfer analysis is performed with commercial CFD solver and is then validated with the experimental data tested at different rotation speed. Then a series of configurations of different thermal boundaries are analyzed to investigate the influence of heat transfer on performance. The simulated results show that the external heat transfer has a negative impact on pressure distribution. The helium gas inside the impeller flow domain is more sensitive to external heat leakage comparing with that inside the diffuser flow. More than that, the mass flow leakage through blade tip clearance is highly affected by the external heat transfer, which counts for the performance degradation.

中文翻译：

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外部传热对超流氦系统中冷压缩机性能的影响

摘要 冷压缩机是开发超流氦温度大容量制冷设施所需的核心部件。压缩机叶轮在极低的温度和低压下运行，由于从机器的热端到冷端的热传递会影响性能，从而影响下游冷火用的回收。为了研究传热对冷压缩机性能的影响，使用商用 CFD 求解器进行共轭传热分析，然后使用在不同转速下测试的实验数据进行验证。然后分析了一系列不同热边界的配置，以研究传热对性能的影响。模拟结果表明，外部传热对压力分布有负面影响。与扩散器流内部相比，叶轮流域内的氦气对外部热泄漏更敏感。不仅如此，通过叶尖间隙的质量流泄漏受外部传热的影响很大，这对性能下降很重要。