压气机叶栅气固耦合的颤振分析研究

【作者】 肖军；

【导师】 周新海；

【作者基本信息】 西北工业大学 ， 航空宇航推进理论与工程， 2004， 硕士

【摘要】 本文在运动网格体系中离散N-S方程，应用Runge-Kutta四步显式的Jameson有限体积格式，并在双时间方法、多重网格法及残差光顺等加速算法的支持下，计算了二维振动叶栅非定常粘性流场。 本文首先研究气固非耦合条件下的振动叶栅内二维非定常粘性流动。假定叶片做平面简谐运动，针对两种叶型分别计算了不同振动幅度、折合频率及扭心位置时的振动叶栅流场，根据各种振型下流场计算结果的比较，分析了振动参数选取对叶栅气动弹性性能的影响。 其次，本文引入叶片结构动力学方程，通过数值求解气动／结构耦合方程体系，研究了气固耦合条件下叶栅内的二维非定常粘性流动，并初步进行了叶栅的颤振分析。针对两种叶型分别计算了不同折合频率下的流场，通过比较振动叶栅相关参数随时间变化的曲线及流场云图，表明折合频率是决定叶片颤振与否的重要因素。 本文最后比较了相同条件下气固耦合与非耦合时叶表气动力的做功情况，其结果表明解除耦合约束后气动力做功有显著变化，为深入研究振动叶栅流场，必须考虑叶片结构动力因素。更多还原

【Abstract】 The Navier-Stokes equation is discretized in the moving-grid system. By adopting the explicit four-stage Runge-Kutta Jameson finite volume scheme, and under the sustainment of acceleration algorithms such as dual-time stepping method, the multi-grid strategy and implicit smoothing of the residuals, a two dimensional unsteady viscous flow in vibrating cascades is simulated.First, a 2-D unsteady viscous flow in a vibrating cascade is investigated under flow-structure uncoupled conditions. Assuming the blades conduct a planar simple harmonic motion, the flows in vibrating cascades in the case of different oscillating amplitudes, different reduced frequencies and different torsional centers are computed respectively for two blade profiles. According to comparing flow calculations at different oscillation modes, the influence of the oscillation parameters’ selection on aeroelastic performances of cascades is analyzed.Second, the structural dynamic equations for blades are introduced in this paper. Through numerically solving the aerodynamics-structure coupled equations, a 2-D unsteady viscous flow in a single cascade is investigated under flow-structure coupled conditions, and a preliminary analysis of the cascade flutter is prosecuted. The flows in the case of different reduced frequencies are computed respectively for two blade profiles. By comparing the time curves of relative parameters in oscillating cascades and the flow field contours under different conditions, it is indicated that the reduced frequency is an important factor to determine whether the blade flutter happens or not.In the end, the situations of work done by aerodynamic forces on blade surfaces when flow-structure is coupled and isn’t coupled under the same conditions are compared, the result indicates that the work done by aerodynamic forces after the coupling restraint is unloaded has a distinct change. In order to deeply study the flows in cascades, the structure dynamic factors must be included.更多还原