No real centrifugal compressor can exactly conform to its design geometry and expected operating conditions due to the uncertainties existing in the manufacturing and operational processes. Such uncertainties have been increasingly recognised to be detrimental to compressor performance. However, quite few studies have focused on the combined effects of geometric and operational uncertainties on compressor performance, and the underlying flow mechanism even remains unclear. In this context, we here present an uncertainty analysis of a centrifugal compressor stage, with both geometric and operational uncertainties taken into account. With the combination of CFD simulation and nonintrusive sparse grid based stochastic collocation methods, the combined and individual effects of total inlet temperature, total inlet pressure, outlet mass flow, impeller tip clearance and hub fillet radius on the stage/impeller performance are quantified and analysed. Particular attention is paid to elucidating the compressor performance variations through flow field and energy decomposition analyses. Results show that the considered uncertainties exert more influence on the compressor stage performance rather than on the impeller performance. Amongst the examined uncertainties, the impeller tip clearance contributes the most to the stage performance. The underlying mechanism lies in that the wake of impeller tip clearance produces distorted flow downstream towards the diffuser, which causes complicated vortex structures and less conversion of kinetic energy to pressure rise in the diffuser passage. The present study lays a theoretical foundation for the further uncertainty quantification and robust design of centrifugal compressors against various sources of uncertainties.

由于制造和运行过程中存在的不确定性，没有真正的离心压缩机能够完全符合其设计几何形状和预期的运行条件。越来越多地认识到这种不确定性对压缩机性能有害。然而，很少有研究关注几何和运行不确定性对压缩机性能的综合影响，甚至潜在的流动机制仍不清楚。在此背景下，我们在此介绍离心压缩机级的不确定性分析，同时考虑了几何和操作不确定性。结合 CFD 模拟和基于非侵入式稀疏网格的随机配置方法，总入口温度、总入口压力、出口质量流量、对级/叶轮性能上的叶轮尖端间隙和轮毂圆角半径进行量化和分析。特别注意通过流场和能量分解分析阐明压缩机性能变化。结果表明，所考虑的不确定性对压气机级性能的影响大于对叶轮性能的影响。在检查的不确定性中，叶轮叶尖间隙对级性能的贡献最大。其潜在机制在于叶轮叶尖间隙的尾流产生向下游流向扩散器的扭曲流动，这导致复杂的涡流结构和动能转化为扩散器通道中的压力升高的较少。