2019.B.4.2. Magnetic Sloshing Damping in Microgravity

Author(s)

Álvaro Romero-Calvo (1)
Gabriel Cano Gómez (2)
Miguel Ángel Herrada Gutiérrez (3)
Elena Castro-Hernández (3)
Filippo Maggi (1)

Space Propulsion Laboratory, Department of Aerospace Science and Technology, Politecnico di Milano, Italy
Departamento de Física Aplicada III, Universidad de Sevilla, Spain
Área de Mecánica de Fluidos, Departamento de Ingeniería Aeroespacial y Mecánica de Fluidos, Universidad de Sevilla, Spain

Session

B.4

Keywords

Sloshing, magnetic liquids, microgravity, attitude control, ferrohydrodynamics

Abstract

The term sloshing refers to the forced movement of liquids in partially filled containers. In a low-gravity environment, the liquid mixes with pressurizing gas bubbles and adopts a random position inside the tank, resulting in unwanted perturbations and a complicated design. Liquid sloshing has consequently been a major concern for space engineers since the beginning of the space era.

The sloshing of magnetic liquids has distinctive characteristics that suggest an interesting approach to this problem. Magnetic fields can be used to shift the natural frequencies and damping ratios of an oscillating fluid. Due to the short range of the magnetic interaction, research has been historically focused on what is known as magnetic liquid positioning. In the age of nanosatellites, however, propellant tanks are much smaller, and the whole fluid volume can be reached with small, low-cost magnets.

The implementation of magnetic sloshing dampers for spacecraft control requires an accurate understanding of basic physics and modelling capability of magnetic liquid dynamics. In this respect, the prediction of the forcing dynamics response of a ferrofluid pushed the authors to develop a dedicated theoretical framework and an equivalent mechanical model for microgravity conditions. The performance of this mechanism was evaluated for a detumbling manoeuvre of a 12U CubeSat with a pair of 2U propellant tanks.

In the framework of the UNOOSA DropTES Programme, four drops will be performed at ZARM’s Drop Tower in Bremen for studying the lateral sloshing of ferrofluids in microgravity. The experiments will be employed to validate the semi-analytical inviscid and CFD sloshing models developed by the authors.