基于流固耦合的重载飞艇副气囊形态分析与试验研究

为了研究非饱和副气囊在重载飞艇升降和巡航过程的形态变化,建立了缩尺比例氦气囊模型。基于向量式有限元(vector form of intrinsic finite element,VFIFE)对副气囊膜结构进行结构动力学分析,并考虑几何大变形和边界非线性;基于有限元法对氦气域和空气域进行流体动力学分析,分别采用自编MATLAB程序和ANSYS软件流体模块独立求解控制方程之后,通过映射网格在CSD(computational structural dynamics)/CFD(computational fluid dynamics)之间进行数据传递并迭代,以实现双向流固耦合。开展了氦气囊的缩尺比例模型试验,对囊体在泄气过程中得到的位移测量值与数值模拟结果进行对比。结果表明,氦气囊在不同充盈度下的形态变化与双向流固耦合数值分析结果一致,证明了该研究提出的数值模拟方法可有效用于副气囊随氦气充盈度变化导致的非稳定形态变化规律的研究。

Morphological analysis and experimental validation of Helium bags of a cargo airship based on fluid-structure coupling

In order to investigate morphological variations of unsaturated floating Helium bags in the ascending/descending and keeping flight of a rigid cargo airship,a scaled Helium bag model was fabricated.Structural dynamic analysis of Helium bag membrane structure was performed based on the vector form of the intrinsic finite element(VFIFE)method,considering geometric large deformation and boundary nonlinearity;fluid dynamics analysis of Helium domain and air domain was modeled with the finite element method.The governing equations were separately solved by self-programmed MATLAB code and ANSYS Flotran module respectively,and the data were transferred between the computational structural dynamics(CSD)and computational fluid dynamics(CFD)through the mapping grid to realize two-way fluid structure coupling.Finally,the scaled model test of the Helium bag was carried out.And the experimental displacement from the Helium bag during the deflation process was compared with the numerical simulation results.The results show that the morphological changes of the Helium bag under different filling ratio are in good agreement with the two-way fluid structure coupling analysis.It validates applicability of the numerical simulation method in the simulation of unstable morphological stage caused by the change of filling ratio.