Numerical Investigation On The Influence Of Non-Axisymmetric Stator On The Sector Cascade Flow Field Under Distortion Conditions

The development of the technologies of gas turbine is an important means to improve comprehensive national strength and enhance international competitiveness.The higher performance index of the engine in the future puts forward higher requirements for the stall margin of the compressor.The designer should consider both the performance and the anti-distortion ability of the compressor in the design stage.The inlet total pressure distortion will cause the separation of the angle region of the stator and even the stall of the angular region,and the stall in the angle region of the stator blade will affect the overall performance and stability margin of the compressor.Therefore,through the modeling technology of non-axisymmetric stator,the angle region separation of stator is controlled so as to improve the stall capability of the compressor anti-separation and anti-angular zone,improve the flow condition of the compressor rotor blade,and improve the performance and stability of the compressor stage to a certain extent.In this paper,the periodicity improvement of sector cascade experimental model is studied.The numerical results show that the periodicity of the flow parameters at the outlet of guide vane and the stator of the sector cascade experimental model can be effectively increased by shrinking the right guide plate and changing the suction pressure at the left guide plate of the sector cascade.The best modification scheme increases the detectable flow channel from 5 to 7 to meet the periodical requirements of the sector cascade experiment.The installation angle of the leading vane No.7 in the front row of the best modified scheme was rotated clockwise by 6 °,resulting the non-uniform flow field at the inlet of the downstream stator vane.The non-axisymmetric stator blade is designed by curved blade modeling for the stator blade whose flow field deteriorated.The static vane modification scheme is when the bending height is 0.3 times leaf height,the bending angle is 10 °,20 °and 30 °;the bending height is 0.5 times leaf height,the bending angle is 10 °,20 °and 30°.The improvement of distorted flow field was analyzed by numerical method.The results show that the inlet flow field of the stator can be simulated by changing the installation angle of the individual guide vane in the front row,and the non-axisymmetric stator blade can effectively suppress angular separation and reduce the range and intensity of the shedding vortex at the outlet of the stator vane which is affected by the distorted fluid,thus reducing the total loss in the stator passage.The modification effect of B6 scheme is the best,and the average total pressure loss coefficient is 7.47%lower than that of rotation experimental model.