Optimal blade shapes for viscous dense gas flows through turbine cascades

The objective of the present study is to find optimal blade shapes providing high turbine efficiency over a large range of operating conditions for turbulent flows trough highly loaded turbine cascades, characterized by high values of the pressure ratio. To this end, a multi-point optimization of the blade shape is undertaken, using a multi-objective genetic algorithm. The flow solver is coupled with a multi-objective genetic algorithm (MOGA). Cascade efficiency has been optimized at several operating points in order to obtain blade shapes providing high system efficiency over a large range of conditions. The mechanism leading to efficiency improvement is a reduction in the maximum Mach number: major gains come from a significant weakening of the trailing edge shock for the optimized configuration