基于CFD/CSD松耦合的直升机配平分析方法

Trim analysis method of helicopter based on CFD/CSD loose coupling

针对直升机配平问题,基于CFD/CSD松耦合策略建立了计入旋翼气弹效应的配平分析方法。旋翼桨叶CSD求解器与旋翼CFD求解器以桨叶弹性轴和变距轴线为媒介,通过线性插值方法交换气动载荷和响应数据。CFD模块和CSD模块在时域内推进,旋翼每旋转一圈交互一次数据,以CFD模块计算的气动力来修正配平计算中气弹分析的气动力输入,直到配平量和CFD气动力在迭代过程中不再变化,即得到耦合配平解。以SA349/2"小羚羊"直升机小速度前飞状态为算例,计算表明所提方法收敛迅速、稳定性良好,计算结果与飞行实测值的对比分析验证了方法的有效性,对桨叶气动力曲线及桨涡干扰等现象具有很好的捕捉能力。

In this paper,a helicopter trim calculation method based on the CFD/CSD loose coupling strategy is proposed.The CSD solver and rotor CFD solver use the blade elastic axis and pitch axis as media to exchange aerodynamic load and response data through linear interpolation method.In the coupling strategy of this paper,CFD and CSD solver operate in the time domain respectively,and exchange the data once per revolution.The aerodynamic force calculated by CFD solver is used to correct the aerodynamic input of aeroelastic analysis in trim calculation,until the trim parameters and CFD aerodynamic force no longer change in the iterative process,and the coupling trim solutions are obtained.In this paper,the SA349/2 helicopter is taken as an example to calculate the forward flight state.The results show that the coupling method in this paper converges rapidly and has good stability.The comparison between the calculation results and the measured flight values verifies the effectiveness of the proposed method,and it has a good ability to capture the aerodynamic curve of blade and the blade vortex distraction.