Multi-objective optimum stator and rotor stagger angle distributions of an axial turbine stage

Gas turbine aerodynamic shape optimization has been the subject of several numerical studies in the past decades. In this research, numerical optimization of a one stage axial turbine is considered. A practical and eective optimization method to improve eciency and/or pressure ratio of the axial turbine is presented. Particular modications are accomplished with a limited number of optimization parameters, by stator and rotor blades re-staggering. A three-dimensional numerical model has been prepared and veried through experimental data, which are obtained from the reference gas turbine engine test rig. Coupling the veried numerical simulation solver and genetic algorithm, the eects of stator and rotor stagger angle distributions on the turbine performance are investigated. The optimization is carried out at the turbine design operating condition. To accelerate the GA convergence rate, the numerical mesh sizes are rened in each generation. As a result, the overall computational time decreases by 20%. Dening two objective functions, this optimization approach resulted in the turbine stage isentropic eciency improvement of 0.85% and 0.86%, in the rst and second objective functions, respectively.