阻尼拉金结构的长叶片透平级气动性能数值研究

文章采用商用计算流体动力学软件ANSYS—CFX数值求解Reynolds—Averaged Navier-Stokes（RANS）方程和标准k-ε紊流模型方法数值研究了考虑阻尼拉金结构的汽轮机长叶片透平级的气动性能．分别计算分析了无阻尼拉金结构、椭圆型阻尼拉金结构和流线型阻尼拉金结构的汽轮机长叶片透平级的流场特性．详细分析了阻尼拉金对长叶片透平级气动性能的影响特性。研究结果表明：阻尼拉金的存在对长叶片流场的影响主要位于叶片吸力面附近。采用椭圆型拉金及流线型拉金长叶片的透平级与无拉金的情况相比，透平级等熵效率分别降低0．313％和0．206％．采用流线型阻尼拉金后透平级等熵效率比椭圆型拉金提高0．107％．相比于椭圆型阻尼拉金结构的长叶片．流线型阻尼拉金结构在其尾缘处的分离涡基本消除．拉金尾缘处的流动损失减少。

Numerical Investigation on Aerodynamic Performance of Long Blade with Damping Snubber

Aerodynamic performance of the long blade turbine stage with damping snubber structure was numerically investigated by using commercial CFD software ANSYS-CFX based on the Reynolds-Averaged Navier-Stokes （RANS） equation and standard turbulent model solution. The characteristics of flow field for the long blade turbine stage without damping snubber, with elliptical damping snubber and streamlined damping snubber structure were calculated. The effect of the damping snubber on the aerodynam- ic performance of turbine stage was also analyzed. The numerical result showed that the isentropic efficiency of the turbine stage with elliptical and streamlined damping snubber decreased by 0.313% and 0.206% by comparison to the consideration of turbine stage without damping snubber. In addition, the isentropic efficiency of the long blade turbine stage with streamlined damping snub- ber increased by 0.107% by comparison to the elliptical snubber case. Comparison with the elliptical damping snubber structure, the separation vortex near the trailing edge of the streamlined damping snubber was eliminated and the corresponding separation flow loss was also decreased.