Variable inlet guide vanes (VIGVs) are widely used for flow throttling and also extending the operating range of centrifugal compressors. Although there are several studies on the effects of adding IGVs on the performance curve of the compressors, none of them have focused on the number of vanes. In the current study, high-fidelity three-dimensional numerical simulations are carried out to analyze the effects of adding VIGVs with different number of vanes on the aerodynamic performance of a single-stage centrifugal compressor. The selected compressor prototype is a high flowrate single-stage compressor equipped with a vaned diffuser, designed and fabricated by Siemens. Computational fluid dynamic simulations are performed for three different number of guide vanes at three IGV inclination angles of 0, −30 and +45 degrees. The numerical results are validated by comparing the pressure-rise curves with the available experimental data of the compressor data sheet, where a good agreement was achieved. Results show that at the fully-open condition, the number of vanes does not have considerable effect on the performance curve of the compressor. However, as the IGV inclination angle increases, the number of inlet vanes plays a considerable role in the compressor efficiency. For example, at IGV inclination angle of +45 degree, increasing the number of vanes from 7 to 11 can increase the compressor maximum efficiency up to 5 points. Numerical results showed that increasing the number of inlet guide vanes imposes a higher pressure drop in the inlet passage of the compressor while generating a more uniform velocity distribution at the suction surface of the impeller. Due to the existence of several counteracting effects, an optimum number of inlet guide vanes can be found.

可变入口导叶 (VIGV) 广泛用于节流，也可扩展离心压缩机的运行范围。尽管有多项关于添加 IGV 对压缩机性能曲线影响的研究，但没有一项研究关注叶片的数量。在目前的研究中，进行了高保真三维数值模拟，以分析添加不同叶片数量的 VIGV 对单级离心压缩机气动性能的影响。选定的压缩机原型是配备有叶片扩压器的高流量单级压缩机，由西门子设计和制造。在 0、-30 和 +45 度的三个 IGV 倾角下，对三种不同数量的导叶进行计算流体动力学模拟。通过将压力上升曲线与压缩机数据表中的可用实验数据进行比较，验证了数值结果，取得了良好的一致性。结果表明，在全开条件下，叶片数量对压缩机的性能曲线没有显着影响。然而，随着 IGV 倾角的增加，进气叶片的数量对压缩机效率起着相当大的作用。例如，在 IGV 倾角为 +45 度时，将叶片数量从 7 个增加到 11 个可以将压缩机最大效率提高到 5 个点。数值结果表明，增加进口导叶的数量会在压气机的进口通道中施加更高的压降，同时在叶轮的吸入面产生更均匀的速度分布。