旋转对内冷通道气膜孔流量系数的影响

Effects of rotating on the discharge coefficients of film holes in turbine blade

关键词:  航空发动机  涡轮叶片  气孔  流量系数  数值仿真

Key words:  Aircraft engine  Turbine blade  Gas hole  Flow coefficient  Numerical simulation

摘要:

为了获得涡轮叶片旋转时对气膜孔流量系数的影响,采用非结构化网格及标准k-ε紊流模型,求解三维N-S方程,对带90°肋和气膜孔出流的旋转矩形通道内的三维流场进行了数值模拟,气动参数变化范围是:通道入口雷诺数Re=60000,150000,罗斯贝数Ro=0,0.11,0.22,气膜孔总出流比为0.22和0.09。Ro≠0时,旋转效应对气膜孔流量系数有明显影响,通道顺时针旋转时,科氏力由上壁面指向带气膜孔的下壁面,引起流量系数增加;通道逆时针旋转时,情况相反。计算结果还表明,在通道内同一径向位置处的两个气膜孔的流量系数是不同的,通道顺时针旋转时,进入左侧孔的流体和气膜孔轴线的夹角小于进入右侧孔的流体和气膜孔轴线的夹角,导致左侧孔的流量系数大于右侧孔的流量系数;通道逆时针旋转时,情况相反。Ro=0时的计算结果与实验数据符合很好。

Abstract:

The effects of the rotation on the discharge coefficient were studied.Numerical simulation was conducted to investigate discharge coefficients of film holes in rectangular channel with both rib-roughened wall and film hole suctions at Reynolds number Re=60000,150000,rotation number 0,0.11,0.22,suction ratio of 0.09 and 0.22.A finite volume method with unstructured meshes was used to solve the three dimensional compressible Navier-Stokes equations.The standard k-ε model was used and the standard wall function was utilized for near wall treatment.The numerical results agreed well with the experimental data of the stationary passages.Investigation was focused on the effects of rotation number on the discharge coefficients of the film holes.The results showed that the discharge coefficients increased when the channel rotated clockwise and decreased when the channel rotated counter clockwise.It also showed that the discharge coefficients of the two film holes at the same radial position were different. The discharge coefficients of the left holes were higher than those of the right holes when the channel rotated clockwise while the discharge coefficients of the left holes were lower than those of the right holes when the channel rotated counter clockwise.