Multicriteria Optimization of Axial Low Pressure Compressor of Gas Turbine Power Plant

The paper shows a method of the gas-dynamic refining of three-stage axial compressor based on the joint usage of mathematical optimization software IOSO and CFD complex NUMECA. The optimizer is used for automatic change of the compressor geometry in order to find the optimal design. The aim was to preserve the original design, for this reason only the geometrical parameters of rotor blades and guide vanes were varied without changing the contours of the meridional flow part and blade roots. The optimization task was multiobjective. It was necessary to find a compromise between the efficiency increase and improvement of the gas-dynamic stall margins of the compressor at the primary operational mode and to prevent the deterioration of parameters at other modes. Compressor parameters were calculated at three engine modes, corresponding to the temperature of the air at the engine inlet — −15 °C, +15 °C, and +45 °C, at each step of the optimization. Parameters of the compressor were calculated in operational and stall points of its characteristics at the modes corresponding to −15 °C and +15 °C. Parameters of compressor were calculated in choking point at the mode corresponding to −+45 °C. The optimization problem was solved in two formulations with different degree of parameters variation at the modes of operation corresponding to the −15 °C and +45 °C. Finite volume model of the compressor that is used in the optimization was created in the meshing software NUMECA AutoGrid. Configuring and solution of the task were carried out in the solver NUMECA FINE/Turbo. Comparison of calculated characteristics of the base compressor with the experimental data was performed before optimization. Analysis of the impact of optimized compressor on the engine operation was performed. The position of the working line of base and optimized compressor variants was indicated. It was shown that optimized compressor has efficiency increase by 1.1% compare to the base while operating as the engine component.