Dynamic analysis of large-scale amplitude liquid sloshingin the spacecraft

Abstract

With the development of space technology, functionalities and life span of the spacecraft are increasing, leading to requirement of a greater proportion of fuels. Liquid sloshing in fuel tanks has more unavoidable effect on the spacecraft. During the attitude and orbital maneuvering of the spacecraft, large-scale amplitude liquid sloshing can be excited with liquid merging and splitting. Generally, theoretical, experimental and numerical methods can be used to predict the dynamics of liquid sloshing. However, most theoretical formulas, like the equivalent mechanical model methods, are only valid for liquid sloshing with small amplitude in simple geometrical tanks. Meanwhile, experimental results are difficult to obtain under a low gravity environment and the accurate measurement of nonlinear liquid sloshing is also a challenge. In most actual simulations, numerical simulation are required. In this paper, based on the smoothed particle hydrodynamics (SPH) method which is a Lagrangian mesh-less method, the linear and angular momentum theorem of the particles system are adopted to calculate the force and moment exerted by liquid against the spacecraft accurately, which avoids the accuracy loss of the pressure field. Moreover, aimed at the low computational efficiency of the common computational fluid dynamics (CFD) method, the impact of particle initial spacing on the accuracy of sloshing force and moment calculated is discussed and enough accuracy of global loads can be guaranteed with fewer particles, which greatly improves the computational efficiency. The time-efficiency of the SPH solver is adequate for embedding into a whole-spacecraft simulation system. Finally, in order to verify the validity of the method, results from SPH method are compared with those obtained by a traditional CFD solver for a 3D liquid sloshing case.