In the automotive turbochargers centrifugal compressor, the volute has a strong potential effect, leading to circumferential nonuniformity of the impeller flow field and compressor stall. In this study, full-annulus unsteady simulations for centrifugal compressors with vaned/vaneless diffusers are carried out. The influence of the diffuser vane on the potential effect of the volute and stall behavior of a centrifugal compressor is studied in detail. Based on the distribution of the casing static pressure, the formation mechanism of the circumferential distribution of static pressure and the reverse propagation process of pressure waves caused by pressure distortion are revealed. The results of this study show that the diffuser vanes can weaken the potential effect of the volute on the impeller flow field by reducing the degree of static pressure distortion. The number of static pressure peaks in the circumferential direction is related to the number of vanes/blades. The diffuser vanes can change the circumferential position of the stall inception, but cannot eliminate the “locking effect” of the volute tongue on the circumferential position of the stall. In other words, the circumferential position of the stall inception is still determined by the volute tongue for a centrifugal compressor with a vaned diffuser. Although the degree of circumferential static pressure distortion inside the impeller is reduced, the stable operating range of the compressor cannot be significantly widened by adjusting the stagger angle of the diffuser vane when the stall first occurs at the impeller inlet.

中文翻译：

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叶片扩压器对离心压气机蜗壳和失速起始潜在效应的影响

在汽车涡轮增压器离心压气机中，蜗壳具有很强的潜在效应，导致叶轮流场周向不均匀和压气机失速。在这项研究中，对带有叶片/无叶片扩压器的离心压缩机进行了全环空非定常模拟。详细研究了扩压器叶片对离心压缩机蜗壳和失速行为的潜在影响的影响。基于套管静压分布，揭示了静压周向分布的形成机理和压力畸变引起的压力波反向传播过程。本研究结果表明，扩压器叶片可以通过降低静压畸变程度来减弱蜗壳对叶轮流场的潜在影响。圆周方向静压峰值的数量与叶片/叶片的数量有关。扩压器叶片可以改变失速开始的圆周位置，但不能消除蜗舌对失速圆周位置的“锁定效应”。换句话说，对于带有叶片扩压器的离心压缩机，失速开始的圆周位置仍然由蜗舌决定。虽然叶轮内部周向静压畸变程度降低，