Numerical Study Of Dimples On The Aerodynamic Performance Of A Transonic Rectangular Compressor Cascade

With the development of modern aero engines,the compressors,which are one of the important components of aero engines,are also constantly developing.The pressure ratio and load of compressors are constantly increasing.As the load increases,the separation and stall phenomena further constrain the performance of the compressor.In compressor stator flow,root angular zone loss and trace loss are often the main components of compressor loss.At present,there are many active and passive control methods for impairment.In this paper,the passive control technology of the dimple on the surface of the blade is used to study the influence of the dimple structure on the flow loss of the leaf type with the 90%height of the DMU37.Its mechanism of action,the study found that the dimple structure can effectively inhibit the separation of the boundary layer,and can reduce the wall shear stress,and the corner flow loss and trace loss are decreased at the near stall condition.The specific work is as follows:Firstly,the CFD numerical study of the original cascade is carried out,and the experimental verification is carried out to verify the feasibility of numerical calculation,and the near stalling angle is obtained.The parameters of the dimple are designed with reference to the existing research.The equidistant dimple structure is arranged,and the commercial software such as CAD,UG,CFX is used for modeling and numerical calculation to explore the effect of the dimple structure under the near stall condition.After the near-stall angle is obtained,the numerical simulation of the dimpled surface of the suction side surface is carried out under the near stall condition,and the influence of the position and size of the dimple on the flow is explored.The results show that the effect is better when the position of the dimple is near the trailing edge.Well,it can effectively reduce the trace loss,and the change of the dimple size has different effects on the flow field.For the research object,when the radius of the intersecting sphere is 0.5mm,the effect is positive.The dimple structure can make the micro-perturbation in the flow,improve the level of the turbulence kinetic energy in the boundary layer,and enhance the separation resistance of the boundary layer,thereby effectively suppressing the separation of the boundary layer and reducing the loss,andimproving the performance.According to the best dimpled case obtained,the variation of condition of the dimple cascade is calculated.The influence of the changing angle and the Mach number on the flow is mainly investigated.The results show that under various working conditions,the dimple structureboth can have a better impact on reducing losses.Although there are negative effects under some working conditions,the impact is small.Finally,the preliminary research on the dimpled surface of the pressure side surface is carried out.It is found that the pressure side surface dimple can better exert the"rolling bearing" effects of the dimple in the flow,effectively reduce the wall shear stress level,thereby reducing the friction loss,and to some extent trail loss has an impact.