Purpose This paper aims to understand the aerodynamic blockage related to near casing flow in a transonic axial compressor using numerical simulations and to design an optimum casing groove for stall margin improvement using a surrogate optimisation technique. Design/methodology/approach A blockage parameter (Ψ) is introduced to quantify blockage across the blade domain. A surrogate optimisation technique is then used to find the optimum casing groove design that minimises blockage at an axial location where the blockage is maximum at near stall conditions. Findings An optimised casing groove that improves the stall margin by about 1% can be found through optimisation of the blockage parameter (Ψ). Originality/value Optimising for stall margin is rather lengthy and computationally expensive, as the stall margin of a compressor will only be known once a complete compressor map is constructed. This study shows that the cost of the optimisation can be reduced by using a suitably defined blockage parameter as the optimising parameter.

中文翻译：

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跨音速压气机转子失速裕度的套管槽优化

目的本文旨在使用数值模拟了解与跨音速轴流压缩机中近机壳流动相关的空气动力阻塞，并使用替代优化技术设计用于改善失速裕度的最佳机壳凹槽。设计/方法/途径 引入了阻塞参数 (Ψ) 来量化整个叶片域的阻塞。然后使用替代优化技术来找到最佳的套管凹槽设计，以最大限度地减少在接近失速条件下堵塞最大的轴向位置处的堵塞。结果 通过优化堵塞参数 (Ψ) 可以找到一个优化的套管槽，可将失速裕度提高约 1%。原创性/价值优化失速余量相当冗长且计算成本高，因为只有在构建完整的压缩机图后才能知道压缩机的失速裕度。该研究表明，通过使用适当定义的阻塞参数作为优化参数，可以降低优化成本。