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为提高直升机前飞状态下旋翼非定常气动弹性载荷的预估精度,在旋翼气动弹性综合分析方法中引入旋翼CFD模块,建立了一套基于CFD/CSD松耦合分析的计算方法和程序。为高效解决流固耦合方法中由于桨叶挥舞、扭转等弹性变形带来的旋翼贴体网格变形问题,采用基于代数变换方法的网格变形技术,桨叶运动变形量和旋翼气动力信息通过流固交接面传递。旋翼流场分析方法中,主控方程采用耦合S-A湍流模型的Navier-Stokes方程,围绕旋翼流场的网格采用结构嵌套网格方法生成,无黏通量计算采用Roe格式,时间推进采用双时间法。旋翼结构分析中,考虑旋翼配平,基于Hamilton变分原理和20自由度Timoshenko梁模型求解弹性旋翼非线性运动方程。分别对CSD和CFD方法进行验证,在此基础上,计算了SA349/2旋翼桨叶在前飞状态下的非定常气动力、挥舞弯矩、摆振弯矩和扭转力矩,并与飞行测试数据进行了对比。计算表明:CFD/CSD耦合方法可以显著提高旋翼非定常气动弹性载荷的分析精度,精确捕捉桨叶表面压强峰值、激波位置等,表明本文发展的旋翼CFD/CSD耦合方法可以有效地运用到旋翼气动弹性载荷的预测分析中。
In order to improve the prediction accuracy of unsteady aerodynamic elastic loads of helicopters in the pre-flight state, a rotor CFD module is introduced in the rotor aerodynamic analysis method to establish a set of CFD / CSD loose coupling analysis based calculation methods and procedures. In order to efficiently solve the problem of deformation of rotor body caused by elastic deformation such as blade waving and torsion in the fluid-structure coupling method, the grid deformation technique based on algebraic transformation method is adopted. The information of rotor blade deformation and rotor aerodynamic information Fluid-solid interface delivery. Rotor flow field analysis method, the governing equations using coupled Navier-Stokes equations SA turbulence model, the rotor flow around the grid grid structure using nested grid method, no sticky flux calculation using Roe format, the time to promote the use of double Time method. Rotorcraft structure analysis, considering the rotor trim, based on Hamilton variational principle and Timoshenko beam model of 20 degrees of freedom for solving nonlinear equations of the elastic rotor. The CSD and CFD methods are validated respectively. Based on this, the unsteady aerodynamic forces, bending moments, shimmy moments and torsional moments of the SA349 / 2 rotor blades in the pre-flight state are calculated and compared with the flight test data Made a contrast. The calculation results show that the CFD / CSD coupling method can significantly improve the analysis accuracy of rotor unsteady aerodynamic elastic loads and accurately capture the peak pressure and shock position of blade surface. It shows that the rotor / rotor coupling CFD / CSD method can be effectively applied to rotor Prediction of aeroelastic loads.