稀释式制冷氦离心压缩机叶轮设计与模拟分析

Design and Simulation Analysis of a Helium Centrifugal Cryogenic Compressor for Dilution Refrigerators

  • 摘要: 氦气在干式稀释制冷机中的循环效率,是决定系统制冷功率与整体效能的关键。传统系统多采用涡轮分子泵进行氦气的预压缩,然而,此类泵不仅对高真空环境有严苛要求、质量流量有限,且其设计并未针对低温工况进行优化。随着对更大制冷量的需求日益迫切,现有技术已逐渐出现瓶颈。论文探讨了离心式压缩机作为实现更大流量氦循环替代方案的可行性。通过对氦气离心式冷压缩机的叶轮进行专门设计与流体力学仿真,初步验证了此技术应用于稀释制冷机循环中的潜力与优势。离心式压缩机有望克服传统方案的限制,为开发下一代大冷量稀释制冷机提供一条可行的技术路径。

     

    Abstract: The circulation efficiency of Helium within a closed-cycle dilution refrigerator is a critical determinant of the system's cooling power and thermodynamic stability. In conventional architectures, pre-compression is typically achieved using turbomolecular pumps. However, these pumps, inherently designed for high-vacuum molecular flow, impose significant limitations on mass flow rates and are not optimized for cryogenic conditions. There is an urgent demand for substantially greater cooling power to manage increasing heat loads, rendering the limited throughput of current pump technologies a growing bottleneck in system scaling. To address these challenges, this study investigates the feasibility of a centrifugal compressor as a high-throughput alternative. A specialized impeller was developed using a combination of the one-dimensional mean streamline method and three-dimensional Computational Fluid Dynamics simulations, with adopting specific speed as a key design criterion. The design targets the unique thermophysical properties of Helium at cryogenic temperatures and low pressures.The simulation results under design conditions demonstrate that the proposed impeller achieves a mass flow rate of 3.6 g/s and a static pressure ratio of 2.34, significantly exceeding the throughput of traditional solutions. The impeller exhibits excellent aerodynamic performance, achieving an isentropic efficiency of 77.16% and a polytropic efficiency of 81.44%. Furthermore, the study analyzes performance under off-design conditions, establishing a predicted surge line to define the stable operating range. It was observed that at excessive rotational speeds, local supersonic regions develop at the blade leading edge, inducing shock losses that degrade efficiency. These findings confirm that centrifugal compression offers a viable, scalable technical path for next-generation, high-capacity dilution refrigerators.

     

/

返回文章
返回