Slip in centrifugal compressors arises from imperfect guidance of the flow by the impeller blades and reduces the work input delivered by the impeller. Slip models are used to predict slip in preliminary design. However, slip models are typically calibrated with data that are not representative of modern aerospace compressors (i.e., pumps, turbochargers, or industrial compressors) and do not account for the variation of slip factor with operating condition. This Paper investigates the efficacy of slip models to predict the slip factor and work input for modern, high-speed impellers at design and off-design conditions. Three slip models are used to predict the performance of four well-known impellers in the open literature. All three slip models generally overpredict the slip factor, and the largest error in the prediction of slip factor typically occurs at maximum operating speed (design speed). In addition, the analysis shows a close correlation between slip factor and two key design parameters of machine Mach number and loading coefficient over the entire compressor operating range. Finally, error propagation analysis shows that the error in impeller work input is proportional to the error in slip factor scaled by the square of machine Mach number and reveals the inherent challenge in accurate prediction of work input for high-speed machines.

离心式压缩机的打滑是由于叶轮叶片对流量的不完全引导而导致的，并减少了叶轮传递的功输入。滑移模型用于预测初步设计中的滑移。但是，滑移模型通常使用不代表现代航空压缩机（即泵，涡轮增压器或工业压缩机）的数据进行校准，并且不能考虑滑移系数随运行条件的变化。本文研究了滑移模型在设计和非设计条件下预测现代高速叶轮的滑移系数和功输入的有效性。在公开文献中，使用三个滑移模型来预测四个众所周知的叶轮的性能。这三种滑移模型通常会高估滑移系数，而滑移系数预测中的最大误差通常发生在最大工作速度（设计速度）下。此外，分析表明，在整个压缩机工作范围内，滑移系数与机器马赫数和负载系数的两个关键设计参数之间具有密切的相关性。最后，误差传播分析表明，叶轮功输入中的误差与滑移因子的误差成正比，该误差由机器马赫数的平方定标，并揭示了在准确预测高速机的功输入中固有的挑战。