高压涡轮封严冷气对主流气动性能的影响

为研究涡轮轮毂封严结构的加入对高压涡轮主流流动的影响,运用数值模拟方法,对无封严冷气喷入的原型和四种封严结构下一级涡轮动静叶的主流流动特性进行细致研究。为保证数值计算的准确性,进行了网格无关性分析和数值方法可靠性验证。研究结果表明:封严结构的加入会降低涡轮动叶效率和级功率,封严冷气射入主流后,冲击主流边界层内的流体,使得局部区域流动发生改变。主流在封严出口处发生流动分离,增大了静叶能量损失,同时影响静叶和动叶流道中通道涡的发展,造成动叶端区流动结构的变化并引起掺混损失。覆叠封严具有的弯曲的封严内部结构,对主流气动性能影响较弱。 

Effects of the rim seal coolant gas on aerodynamic performance of mainstream flow in high-pressure turbine

In order to research the effects of the rim seal on the mainstream flow in a high-pressure turbine,the mainstream flow features of the original no-coolant gas ingestion and the four kinds of seal types for a turbine stage were compared.The analysis of computational grid independence and reliability validation for the numerical method was performed to guarantee the accuracy of the numerical calculation. The study shows that seal structure will reduce the efficiency of rotor and the stage power. The sealing flow injected through the rim seal interacts with the boundary layer of the mainstream flow,changing the flow of the partial areas. The mainstream flow separated at the outlet of the seal will increase the energy loss of stator and affects the development of passage vortex in the turbine stage.It plays a significant role in the formation of secondary flows as the major contributor to the aerodynamic losses in turbine passages. The rounded shape inside the compound seal has a reduced influence on aerodynamic performance of the mainstream.