Magneto-Hydro-Dynamics Liquid Wheel Actuator for Spacecraft Attitude Control
Abstract
A novel actuator for spacecraft attitude control with liquid flywheel is presented. The main characteristic of this new concept of reaction wheel is that a conductive liquid rather than a solid mass is accelerated to change the angular momentum of the equipment and, as a consequence, to provide torque to the spacecraft. The conductive liquid is accelerated using a conductive Magneto-Hydro-Dynamic (MHD) pump. Two different configurations of the device have been studied on the basis of the optimization of the dimensionless moment of inertia and the minimization of the viscous shear. A 2-dimensional Finite Difference Hybrid Model (FDHM) has been developed on the basis of the MHD set of equations under the hypothesis of low Magnetic Reynolds. The model solves numerically the time dependent axially symmetric problem of an electrically conductive liquid rotating in a torus with rectangular cross section due to the interaction of a radial magnetic field and an axial electric field. The electric side of the problem has been solved by means of the node method applied to a network of electric resistances and voltage generators representing the back electromotive voltage induced by the spinning liquid through the magnetic field. The fluid-dynamics side of the problem has been solved using a Crank-Nicolson method over a non uniform and collocated grid. The grid generator has been written to be sensitive to the Hartmann number of the problem. Several simulations has been made, over 600,in order to test the FDHM and in order to outline the performances of the device. The model has been tested numerically checking the accuracy of the computed dynamic and electric quantities.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 26, 2017
- Accession Number
- AD1026179
Entities
People
- Fabio Curti