Computational fluid dynamics simulation of surge in a three stage axial compressor

A three dimensional unsteady Reynolds-Averaged Navier-Stokes solver was used to perform multistage unsteady simulations of a three and half stage compressor. Previously published research presented the simulation of the same compressor with mal-scheduling of the variable stator vanes (VSV) and predicted a rotating stall pattern in all stages. The nominal VSV schedule compressor was simulated to provide a reference case for comparison purposes. The compressor’s behaviour in the nominal case seemed to behave against conventional wisdom with mass flow and pressure fluctuations representing compressor surge. However further analysis showed that inherent design feature in the compressor which had a highly loaded third stator was the primary cause of surge initiation, a situation which was eased with mal-scheduling by unloading that stator. Full analysis of the simulation results of the nominal case and discussion are presented in this paper.