Experimental investigation of turbulent wake–blade interaction in axial compressors

Abstract

Abstract The fundamentally unsteady character of flow in multi-stage turbomachines is traditionally neglected in most of the flow calculation methods. The rapid development of hard- and software for numerical flow simulation has opened possibilities for investigation of the unsteady flow in turbomachines. The still existing methodical problems in the simulation especially of turbulent flow makes the experimental validation of numerical results indispensable. In a low-speed research axial compressor with incompressible flow conditions and relatively large geometric dimensions, a flow measuring system based on split-film probes has been installed and extensively operated. Measurements of the unsteady flow field and the turbulence properties concerning the blade wakes have been made and reported. In the subsequent investigation, the passage of the IGV wakes and the rotor blade wakes of the first rotor through the adjacent stator blade row have been explored in one measuring plane in front of the stator, four measuring planes within the stator and a measuring plane behind the stator at the mean radius of the blading. Measurements of the unsteady absolute velocity field in the S1-plane and the turbulent fluctuations have been made. The transportation of the IGV wake through the stator is one result of the measurements. The decay of the fluctuation components inside the stator blade row has been investigated in detail.