An Estimation Approach for Propellant Sloshing Effect on Spacecraft GNC

Liquid propellant sloshing induces perturbations to spacecraft Guidance Navigation and Control (GNC) due to coupling between fluid motion and dynamic behavior of the spacecraft. Therefore, liquid sloshing in spacecraft fuel tanks is a conspicuous problem. An approach based on sloshing equivalent mechanics is proposed in this paper to estimate effect of propellant sloshing and improve efficiency of the estimating process. A mechanical model is built by use of Computational Fluid Dynamics (CFD) tools and packed as a module to be utilized in GNC simulator. Then the close-loop outputs obtained are treated as new boundary conditions for CFD tools, and the equivalent mechanics are upgraded according to the new CFD results. The accuracy of the approach is demonstrated by a system with presumed parameters. Finally, the deducing process is applied to a practical example, which rapidly and accurately estimates the effect of propellant sloshing on the GNC, thereby validating efficiency of the approach.