Effect of axisymmetric endwall contouring on the high-load low-reaction transonic compressor rotor with a substantial meridian contraction

For a high-load low-reaction compressor transonic rotor based on an increase in outlet axial velocity, the stage reaction is decreased by a substantial meridian contraction of the endwall. The axisymmetric endwall contouring has a deep impact on the aerodynamic performance of the rotor. Therefore, nine combinations of endwall contours with three different shapes including a linear wall, a sinusoidal wall and a symmetrical wall of the sinusoidal wall about the linear wall were firstly studied through 3D steady Reynolds Average Navier–Stokes simulations. The results show that the cases with a linear hub have the highest peak pressure ratio and the largest peak efficiency, whereas the cases, featured with a sinusoidal hub, have the widest stall margin, the largest mass flow and the lowest pressure ratio. Endwall contouring not only influences the shock structure across the flow passage but also dominates the location and intensity of separation. In addition, the effect of endwall contouring on loading distribution is also presented and the case with a sinusoidal hub is characterized by aft-loading and the other two cases have a feature of fore-loading.