Flow Computation and Blade Cascade Design in Turbopump Turbines

The aerodynamic blade cascade design of a two stage axial supersonic turbine is investigated by using an inviscid flow computation method. The flow inside such kind of turbine is characterized by high inlet Mach numbers and large deflection angles as well as supersonic flow matching between stator and rotor. Most of the computed flow configurations give strong shock waves in the blade-to-blade channels, which let anticipate boundary layer separation phenomena. The inverse mode calculation is applied in order to avoid adverse pressure gradients on the walls. The semi-inverse method allows us to get the geometry of a blade profile corresponding to a given pressure distribution on the suction side and the pressure side, the solidity being fixed. A new design of the turbine blade cascade is then considered in order to achieve the desired velocity diagram.