Effects of non-axisymmetric IGV wakes on a low speed axial compressor

Based on the axisymmetric wake impact experiment, several non-axisymmetric wake impact experiments were carried out. When the number and circumferential positions of inlet guide vanes (IGV) were logical, the wakes of non-axisymmetric IGVs could make beneficial unsteady excitation on downstream rotor field. In these experiments, some suitable non-axisymmetric wake impact plans worked better than the axisymmetric wake impact plan. As compared to the axisymmetric wake impact plan, the non-axisymmetric wake impact plan could supply multi-frequency exciting signals. In addition to the beneficial high-frequency signal, the non-axisymmetric plan B generated a low-frequency square-wave exciting signal and some beneficial secondary signals. Based on the unsteady cooperative flow theory, the exciting wakes in non-axisymmetric plan were easier to cooperate with complicated vortices in a compressor, such as clearance vortices, passage vortices and separated vortices. The non-axisymmetric wake impact plan B in this paper could make the max efficiency increase by 1.2%, total pressure rise and stall margin rise by a little.