Study On Aerodynamic Performance Of Boundary Layer Suction For A Highly Loaded Subsonic Compressor Cascade

Gas turbine,as the "Pearl of the crown" in the field of power machinery and equipment,is an important symbol of national science and technology and industrial strength.As one of the three main components of gas turbine,the load and stable working range of compressor will affect the life,efficiency and stability of gas turbine.As the active flow control technology of the compressor,the boundary layer suction can weaken the thickness of the inlet boundary layer,restrict the development of the transverse two flow and restrain the separation of the suction surface/end wall corner.Therefore,it is of great significance to study the boundary layer suction to improve the aerodynamic performance of the high load diffused cascade.In this paper,the effect of suction on the aerodynamic performance of the cascade is investigated by numerical method,and the optimum suction scheme is selected for experimental verification.In order to weaken the thickness of inlet boundary layer,the influence of end wall circumferential groove suction on aerodynamic performance of cascade is studied.In this paper,respectively on the 16.6%chord ahead of the leading edge,the leading edge,leading edge after 16.6%chord and 33%chord opening suction slot,suction flow rate are 0.5%and 1%.It is found that the circumferential groove suction can effectively weaken the thickness of the inlet boundary layer and increase the kinetic energy of the inlet boundary layer,effectively postponing the separation of the suction surface/end wall corner area,the passage vortex core strength decreases,and the blockage of the flow passage is improved,and the loss is reduced.The best suction position exists under the different suction flow.In order to explore the effect of different suction schemes on the aerodynamic performance of cascades,a numerical study on the suction of end wall to flow holes is carried out.The suction hole is based on the suction surface of the blade,arranged in an arc line,and along the flow direction.Each scheme is 3 suction holes,and the suction flow rate is 0.5%,1%,1.5%and 2%.It is found that the flow hole suction can reduce the development of the transverse two flow,and the separation of the suction surface/end wall corner is suppressed,the separation range of the corner region is greatly reduced,the initial position of the channel vortex is moved to the backside of the suction hole,and the flow state of the cascade is improved.According to the numerical results,the best scheme of flow hole suction is experimentally verified.It is found that the loss of the middle diameter of the prototype cascade increases after the suction,the loss and separation range of the corner area decrease,and the rate of loss reduction decreases with the increase of suction flow.Through the study of the variable incidence of the prototype cascade,it is found that the loss decreases first and then increases with the increase of the incidence,and the loss is the smallest at i=-3°.After suction,it is found that the loss decreases first and then increases with the increase of the incidence,and the maximum loss decreases at i=0°.Bur under the positive incidence,the loss increases and the separation intensifies.