Multicriteria optimization of the working process of axial compressor of gas turbine engine taking into account its multimode operation

The article presents the results of optimization of the working process of axial compressor of gas turbine engine due to optimization software IOSO and CFD software NUMECA Fine/Turbo. Optimization was performed by changing the shape of rotor blades and guide vanes. The shape of meridional contours path was not changed. Parameters of the compressor were calculated in three mode of engine operation corresponding with a low, standard and high temperature of the inlet air. It was set restrictions for the LPC specific massflow, minimal pressure raise and stall margin. The coordinates of three points of a spline in circumferential direction and stagger angle were changing for the rotor blades. The coordinates of a mid-point and a point of trailing edge, stagger angles and also shifting of sections in circumferential and axial directions were changing for the guide vanes. The value of static pressure also was changing during optimization process. As the result of the solution of optimization problem, pareto set between increase of compressor efficiency and increase of stall margin was obtained. One point of the Pareto set met all the required parameters of the modernized LPC. The LPC geometry that guaranteed efficiency increase of 1,2%, total pressure ratio increase of 2,6% and the same specific massflow in comparison with the original LPC was obtained as a result of the investigation. Characteristic of the new LPC is different from the base LPC characteristic. Therefor thermodynamic calculation of NK36-ST engine was conducted again to know influence of the optimized LPC.