Unsteady Simulation of Shrouded Axial Compressor with Cavity

Abstract

Numerical analysis which modeled blade and cavity in shrouded axial compressor is conducted. In this investigation, flow field of downstream cavity trench is discussed. It is assumed that only upstream stator and downstream rotor are affected in that field. To conduct unsteady analysis, phase lag technique is implemented. The simulation reveals that pressure is dominated by potential effect driven by downstream rotor leading edge in that field. Unsteady fluctuation of pressure occurs because of rotation of rotor. Perturbation of velocity is generated by the fluctuation of pressure. However, it is revealed stator also causes significant effect in case of velocity field at downstream cavity trench. Three-dimensional separation occurs near hub suction side of stator blade. After main flow passes recirculation region of the separation, the flow has higher negative radial velocity. Therefore, it is observed that ingress is stronger in wake region that passes hub corner separation. Stronger ingress causes higher axial velocity near cavity trench since ingress transfers axial velocity of mainstream flow.