Numerical simulation of fluid-thermal-structural coupling characteristics of stratospheric non-rigid airship

The voluminous stratospheric non-rigid airship is very sensitive to the external thermal environment. The temperature change of internal gas caused by the variation in the external thermal environment and wind speed will lead to a change in the shape and buoyancy of the airship, thereby affecting its flight control. The traditional static analysis method is difficult to accurately reflect this fluid-thermal-structural coupling process. In this paper, the iterative analysis method was established for the fluid-thermal-structural coupling effect of stratospheric non-rigid airship based on the models of fluid, thermal, and structural deformation. Considering the load such as the internal thermal effect and external flow field of the airship, the simulation of the thermo-induced structural deformation effect was conducted using Fluent and Abaqus software. The influence of local time and external wind speed on the structural deformation, volume, and equilibrium altitude of the airship was analyzed. The results demonstrate that, at low wind speed, the influence of aerodynamic pressure on the deformation of the airship is negligible. However, a great amount of heat is carried away by the wind, then the structural deformation caused by internal and external pressure difference is alleviated and the equilibrium altitude of the airship change obviously. This can serve as a guideline for the design and flight test of the long-endurance stratospheric non-rigid airship.