Application Study Of Fence In Static Flow Field Under The Condition Of Non-uniform Inlet

As a core component of aero-engines,the performance of compressor has a significant impact on the entire engine.During the cruise,the inlet flow field is often non-uniform,resulting in enlargement of corner separation,increasing of flow loss,and then affect the normal operation of the entire engine.Therefore,improving the aerodynamic performance of compressors under non-uniform inlet conditions has become an important part of gas turbine development and research.As a boundary layer isolation device,fence can block the migration of low-energy fluids and delay the boundary layer separation in the hub-corner region.A lot of researchers have been found that the fence can play a positive role in reducing flow loss.Considering that the non-uniform inlet condition will increase the migration of low-energy inside the stator passage,this flow characteristic is beneficial to the utilization of fence.What’s more,considering the three-dimensional characteristics of flow field,this research is based on section-shaped cascades.This paper takes the section-shaped compressor experimental cascade as the research object,which was designed by the in-house research group.Based on the numerical method,the effects of fence are investigated on the flow field of the stator under non-uniform inlet conditions.Firstly,a non-uniform inlet condition is formed by rotating some inlet guide vane.Meanwhile,the flow passage affected by the non-uniform inlet conditions is chosen as the target flow passage for the application of fence.Secondly,in order to investigate the effect and influence regular pattern of the fence,some structures with different positions and sizes are arranged on the hub or suction surface by analyzing the total pressure loss coefficient of the target flow passage,the parameter of the S3 flow surface of the stator outlet and the limiting streamlines of the suction surface.To ensure the efficiency of the calculation and the accuracy of the results,fully structured grids are used to the cascade,while the grid density near the fence is encrypted.The results show that,under the condition of subsonic flow,the fence can effectively reduce the flow loss of the stator passage,which was affected by the non-uniform inlet conditions.A 20.3%loss reduction can be acquired with the best fence scheme which is installed on the hub surface near the pressure side of the blade and concretely located at 15%pitch location away from pressure surface.Conversely,the suction surface fence leads to complicated vortex structures due to the strong interaction with the low-energy fluid inside the hub-corner region,which increases the flow loss in the corner region and has little effect in reducing the total loss coefficients.However,it is worth noting that the fence can effectively restrict the migration of low-energy fluids in the most configurations.