EUCLID satellite: Development of a lumped parameter model for sloshing description

This paper presents a research work estimating the impact of propellant sloshing on the pointing-stability of the EUCLID satellite, for a pre-design phase of the project. The analysis is carried out by means of a simplified lumped parameter model describing the fluid system. This model allows the identification of forces and angular moments due to liquid movement under different acceleration conditions, and for different fill levels of the reservoir. The lumped model is calibrated by means of CFD simulations to determine the correct values to be attributed to the different coefficients. For this work, two tank fill ratios have been considered: 22 and 50%, with an elastomeric and deformable bladder. The results of the lumped models are compared with the CFD output obtained using the same acceleration profile, and corresponding to the same fill level. The study shows that using CFD to calibrate the lumped parameter model is a promising technique, which can be applied at a preliminary design stage, to reduce development costs and time. This work is intended as the prosecution of the first study about sloshing by the same authors, which was aimed at representing bladdered tanks using computational fluid dynamics without recurring to fluid–structure interaction techniques. Here, a new method for the calibration of the traditional sloshing lumped model, based on computational fluid dynamics instead of real experiments, is proposed and applied to a specific fluid system. This procedure can result in a consistent reduction of the experiments costs.