Numerical Investigation of the Flow Field and Aerodynamic Load on Impellers Under Radial Inlet Guide Vanes With Trailing Edge Blowing in Centrifugal Compressor

Abstract

The radial inlet is a typical upstream component which is widely used in multiple-stage centrifugal compressors or blowers. Adding the guide vane in the radial inlet could improve the flow field along circumference distribution and increase the efficiency of the compressor as well. However, the guide vane in the radial inlet generates the wake which causes the Rotor-Stator-Interaction (RSI) and further raises the issue of impeller fatigue failure. In order to compensate the wake effect caused by the guide vane, the active control of trailing edge blowing (TEB) is adopted. Based on Computational Fluid Dynamics (CFD) simulation, the radial inlets with unevenly distributed guide vanes (UGV) are considered. This study investigates the guide vane wake in a radial inlet with or without TEB, and aims to figure out the flow phenomenon in radial inlet and the aerodynamic load on the downstream impellers. The simulation results show that the trailing edge blowing has effect on the compressor performance and reduces the wake intensity. By conducting unsteady simulations, the aerodynamic load on the impeller’s leading edge is obtained for the radial inlets with or without TEB. The dominant frequency and the pulse amplitude are obtained by Fast Fourier Transforms (FFT). Compared with the UGV model, the TEB shows lower excitation at the harmonics of the impeller passing frequency, and has little influence on the amplitude at the impeller rotation frequency. It means the TEB could improve. the safety of the impeller under radial inlet guide vane condition.