Treffer: Comparative Study Between MEMS and Conventional Thrusters for Small Spacecraft Micropropulsion

Miniaturization of spacecraft has been gaining wide interest in the space industry, given its potential for reducing space missions' costs and providing a novel approach to enhancing and facilitating spaceflight. Recently, a lot of research has been successfully put into this field along with the advancements that make it more feasible, though a major obstacle to achieving the new generation of spacecraft is the technical challenge of fitting a suitable propulsion system. Useful chemical propellants are usually corrosive, flammable, and/or toxic, so alternatives need to be found. The aerospace industry is shifting towards green and nontoxic propulsion systems, so water could be used as an effective propellant, considering its relatively high mass density and low molecular mass. New microelectromechanical systems (MEMS) technologies show promising opportunities for the integration of miniaturized propulsion systems, due to their versatility and robustness. In this thesis, a comparative study of nozzle flow, heat transfer, and thermodynamics in two different thrusters is conducted. One thruster is based on MEMS, with a typically quasi-2D geometry, while the second thruster is based on more conventional technologies and manufacturing techniques, with an axially symmetrical 3D shape. After briefly introducing micropropulsion and discussing the propellant selection and nozzle fabrication along with the background theory related to micropropulsion as well as the analytical and OpenFOAM numerical (DSMC, continuum, and a hybrid approach containing both to accommodate to the variation in Knudsen number throughout the computational domain) modeling methods, the used methodology is based on using OpenFOAM's DSMC solver (dsmcFoam+) following the mesh creation using blockMesh and snappyHexMesh and developed analytical model (using MATLAB and CoolProp) along with an additional VLM ANSYS Fluent CFD model prepared in advance at TU Delft, where their (steady state as well as transie
Mechanical Engineering