Mitigation of axial flow turbine losses by an optimised bump hub wall treatment

The change in turbine stator 1 and rotor hub surface shapes has a significant effect on the reduction of the turbine secondary flow losses. This reduction was implemented by boosting the aeroderivative optimised bump hub wall treatment in turbine stage hub surfaces that reduced results from the reduction of the turbine flow separation losses. The method was contrasted with the Aachen Turbine's traditional axisymmetric hub surface, which is a widely used industrial design. This stopped the pressure side horseshoe cyclone from merging with the suction side stem. This led to a decrease in turbulent kinetic energy in the interaction zone between the turbine stage. By using a hub shaped by the optimised bump, a 6.19% reduction in the total pressure loss coefficient predicted by OpenFOAM is expected as compared with axisymmetric hub in both stator 1 and rotor. A Kriging surrogate model is used to predict the best surface parameters for the optimised stator 1 and rotor hub surfaces. It is anticipated that the greater turbine stage isentropic efficiency will improve the profitability by 0.26%.