低温透平膨胀机制动叶轮的优化设计

Optimal design of brake impeller for cryogenic turbo-expander

随着低温透平膨胀制冷机制冷量的不断增加,对整机的性能不断提出更高的要求,然而,对制动端的关注仍然很低,制动端中制动叶轮是核心部件,制动叶轮的性能提升可以使整机性能提升。对制动叶轮进行优化,使用了两种优化策略,策略一对子午流面和叶型依次进行优化,策略二对子午流面和叶型同时进行优化,两种优化策略都始终以制动功率为约束,经过多次优化,得到优化结果。与原始模型对比,优化模型气动性能显著改善,使用策略一效率提升10.61%,使用策略二效率提升10.14%,工作范围均显著扩大。分析表明,相比原始模型,优化模型泄露损失、回流损失、尾迹掺混等显著减少,不同策略优化的结果也略有不同。

As the cooling capacity of cryogenic turbo-expansion refrigerators continues to increase, higher requirements are continuously placed on the performance of the whole machine. However, attention to the brake equipment end is still very low. The brake impeller in the brake end is the core component. The performance improvement of the brake impeller can achieve the performance of the whole machine. To optimize the brake impeller, two optimization strategies were used. The first strategy was meridian flow surface and blade shape was optimized one by one, and the second strategy was to optimize the meridian flow surface and blade shape at the same time. Both optimization strategies always constrained the braking power, and the optimization result was obtained after many times optimizations. Compared with the original model, the aerodynamic performance of the optimized model is significantly improved, the efficiency of using strategy one is increased by 10.61%,the efficiency of using strategy two is increased by 10.14%, and the working range of using strategy one and strategy two is significantly expanded. The analysis shows that compared with the original model, the optimization model has significantly reduced leakage loss, recirculation loss, wake blending, etc., and the optimization results of different strategies are also slightly different.