Study On The Weakening Of Transonic Turbine Shock Wave And Turbine Serialization

Turbine,as an important part of impeller machinery,has a pivotal influence in the fields of aviation,marine and power generation.With the development of the times,turbines have begun to develop in the direction of high load and high pressure in order to achieve higher power.However,the design of large expansion ratio will cause the airflow speed in the turbine cascade to increase,and the Mach number increases,especially in the flow channel.At the speed of sound,serious shock loss is caused,which makes the aerodynamic performance of the turbine drop sharply.Therefore,in order to achieve high-load and high-pressure turbine aerodynamic design,it is necessary to develop a transonic turbine blade design method to weaken shock waves and reduce aerodynamic losses.This paper takes the self-designed transonic turbine cascade as the research object,studies the internal flow field structure and shock loss mechanism,and discusses the shock wave weakening method.First,the numerical simulation method is used to study the internal flow field of the original turbine cascade,and the complicated wave system structure at the trailing edge and the loss mechanism of shock wave/boundary layer/wake mutual interference are analyzed in detail,which provides a theory for discussing the method of weakening shock wave.basis.Analyze the influence of different exit Mach numbers on the trailing edge shock wave,which is mainly reflected in the influence of the position,form and intensity of the shock wave system.Then,because the designed turbine is a meridian expanding and twisting blade,the flow field conditions at different blade heights are different.The distribution law of the turning angle of the trailing edge of the stator blade along the blade height is discussed to weaken the three-dimensional shock wave of the blade.The results show that the Mach number at the root of the leaf is larger,the smaller the turning angle of the trailing edge is selected,and the curvature of the suction surface from the throat to the trailing edge is small,the shock wave is weaker;the Mach number is smaller at the tip,Choose a proper turning angle of the trailing edge and increase the curvature of the profile line from the throat of the suction surface to the trailing edge,the flow field is better.When analyzing the impact of the trailing edge radius on the shock wave,the pressure changes in the basement area and the previously neglected separation shock wave were analyzed in detail,which reasonably explained the reason why the shock wave is weakened when the trailing edge radius is small.In order to further reduce the shock loss,the front edge of the suction at the root of the blade is affected by the front row shock,and the curvature change law is discussed to ease the radial flow of the airflow and reduce the secondary loss.Finally,the low shock loss cascade design method is used in the turbine stage and compared with the original transonic turbine.The results show that the total static efficiency of the turbine has been improved,the flow field has been improved,and the turbine performance analysis at non-design points,Further verify the effectiveness of the shock wave weakening method.By adopting the method of cutting top + rotating stator blades,the low shock loss turbine is serialized and expanded,and the total static efficiency of the turbine can reach the standard within the range of flow matching.