Numerical Investigation Of Controlling Secondary Flow In High-speed Compressor Cascade Using Endwall Fences

As an important part of gas turbine,compressor plays an important role in performance.The rapid development of the gas turbine to compressor has higher load and pressure ratio,the gradient of the flow pressure was also increased along the transverse direction.This phenomenon has brought the compressor performance,leading to complex secondary flow on endwall.Nowadays,the aerodynamic load in the cascade has been continuously improved with the development of flow control technology.The three-dimensional flow characteristics in the grid are becoming more and more obvious,and the secondary flow and its losses are further strengthened.It has been proved that the application of the end wall blade technique to the low-speed compressor cascade.In this paper,a detailed numerical simulation has been carried out for the high-speed plane compressor cascade composed of NACA65-K48 straight blades equipped with fence on the blade endwall to find the influence of single parameter variation on flow field structure and aerodynamic performance.By means of analysis,the optimum geometry and position parameters of endwall fence are obtained under design condition.The analysis suggest that the endwall fences in high load diffusion cascade also the effect of controlling boundary layer.On the one hand,the fence prevents the crosswise flow and the pressure side branch of the passage vortex from moving towards the suction surface near the endwall of cascade.On the other hand,the counter-rotating streamwise vortex induced by the endwall fences can enhance the momentum exchange between the endwall boundary layer and the high momentum freestream fluid,and reduce the unevenness of the airflow in the outlet section.Finally,the range of corner separation and the loss of cascade is reduced.The outlet flow field of this high-speed compressor cascade is composed of corner vortex,concentrated shedding vortex and passage vortex.The optimal endwall fence which weaken the range and strength of the passage vortex and the shedding vortex and cause the wall corner vortex to dissipate in advance,can simplifies the vortex structure and reduces the total loss of cascade by 6.42%.