| Compressor is one of the most important components in aero engines,the stability and efficiency directly determine the performances of the entire engine.If there are not a wide and stable operating range in compressor,the safety performance of the entire engine will be reduced.At present,the slot casing,which is a simple casing treatment method for improving the stability margin of the compressor,has received more and more attention.This paper systematically studies the stall mechanism of NASA’s transonic rotor Rotor37 using simulation methods,and it analyzes the stability expansion and stabilization mechanism of the circumferential single-slot and circumferential five-slot casings.Finally,the orthogonal design optimization method is used to comprehensively analyze the effects of several typical parameters on the efficiency and stability of the compressor rotor.The regression equation established by multiple regression analysis is used to predict the experimental results.First,the working state of the rotor with a smooth wall casing under design conditions was calculated using CFD simulation methods,and the simulation results were compared with the experimental results to verify the accuracy of the simulation results.The simulation results of different outlet pressure states are compared and analyzed,and the causes of the stall of the rotor with a light-walled case are comprehensively analyzed,which provides guidance for the design of the case slotting model.Then,the model of the casing with the circumferential single slot and the circumferential five slot was established.By using simulation methods,the stall cause and stability expansion mechanism of the rotor with the circumferential slot casing under different outlet pressure conditions were compared,which provide a basis for orthogonal test parameter selection.The research results show that with the increase of outlet pressure,the leakage flow from the tip of the blade forms a leakage vortex,and a large low-speed region is formed at the trailing edge of the suction surface and at the front the leading edge of the pressure surface of the blade,which causes blockage of the tip and axial flow capacity reducing;both single-slot and five-slot processing methods are used to limit the tip leakage flow in the circumferential slot,which can reduce the low-velocity region of the front edge leakage vortex at the higher leaf height and the separation of the surface layer of the trailing edge of the suction surface to improve the stability of the compressor.Finally,the orthogonal test and the regression analysis are used to optimize the design of the slotting model.The weight of several key parameters of compressor and casing slotting on the efficiency and stability of the compressor was analyzed,and the regression equation was established by using multiple regression analysis to predict the test results and verify the accuracy of the regression equation.The results of orthogonal experiments show that the compressor rotation speed has the greatest effect on the compressor stability margin and peak efficiency,and the optimal combination of stability margin and peak efficiency is obtained. |
