基于双向流固耦合的长叶片气动和强度性能的数值研究

Numerical Investigations on Aerodynamic and Mechanical Performance of Long Blade Based on Two-Way Fluid-Structure Coupling Approach

关键词:  长叶片  气动性能  强度性能  双向流固耦合  数值模拟 

Key words:  Long Blade  Aerodynamic Performance  Mechanics Performance  Two-Way Fluid-Structure Coupling  Numerical Simulation

摘要:

为了研究流固耦合对长叶片气动及强度性能的影响,采用双向流固耦合技术对一典型长叶片进行了详细的数值分析。采用动网格技术和数值求解Reynolds-Averaged Navier-Stokes(RANS)方程的方法进行长叶片气动性能分析,耦合长叶片气动性能分析得到的叶片表面压力分布,采用商用软件ANSYS研究了考虑阻尼围带和拉金结构的长叶片的应力和变形特性,利用叶片表面节点位移和气动压力在流固耦合面上保证能量守恒的条件下采用插值传递方法,经过迭代得到稳定的长叶片气动及强度性能。结果表明:耦合前后长叶片表面的静压分布的差异主要集中在上部区域。基于双向流固耦合作用得到的长叶片绝对出口气流角在40%~95%叶高范围内相比于没有考虑流固耦合作用时减小。耦合前长叶片最大位移位置出现在85%叶高处靠近前缘位置。耦合后长叶片的最大位移位置由前缘移向尾缘,最大位移值由3.471mm减小到3.082mm。长叶片最大等效应力出现在叶片压力面侧第一级榫齿上表面靠近前缘处。耦合前后应力分布趋势基本不变,最大应力的位置不变。耦合后最大应力值提高0.4%。 

Abstract:

Detailed numerical investigation of a typical long blade based on the two-way fluid-structure coupling approach was conducted in order to study the effects of fluid-structure method on aerodynamic and mechanical performances. Aerodynamic performance of long blade was analyzed using mesh deformation and Reynolds-Averaged Navier-Stokes (RANS) solutions. The mechanical performance of long blade with the damper shroud and snubber was conducted using finite element analysis approach with consideration of the surface aerodynamic pressure and nonlinear contact between adjacent damping tip-shroud and snubber. Nodes displacement and aerodynamic pressure of blade surface were interpolated in the fluid-solid coupling surface for maintaining the energy balance. Stable long blade aerodynamic and mechanical performances were obtained by several iterations. The numerical results show that the difference of static pressure distribution with and without coupling is mainly located at top half of long blade. Absolute outlet flow angle decreases in the range of 40%~95% span with consideration of fluid-structure coupling. The maximum displacement of long blade appears at the 85% span near leading edge without coupling effect. The maximum displacement position moves from leading edge to trailing edge and the quantitative value changes from 3.471mm to 3.082mm with consideration of fluid-structure coupling. The maximum Von-Mises stress of long blade appears on the first tooth upper surface near leading edge of blade pressure side. Von-Mises stress distributing trend and the location of the maximum Von-Mises stress are the same with and without coupling effect. The maximum Von-Mises stress increases by 0.4% with consideration of fluid-structure coupling effect. 