The overall aim of this project is to develop a numerical model for Solid state Pulsed Plasma Thrusters (PPT) that will allow their performance to be optimized. Solid state Pulsed Plasma Thrusters (PPT) are an established technology for compact spacecraft propulsion systems. PPTs have been effectively used on small satellites for various roles such as attitude control, orbital station keeping, de-orbiting for a controlled atmospheric re-entry. Although PPT optimization has been performed previously it was done using simplified assumptions about propellant ablations and associated effects on the plasma. Most of the advanced models have been developed for gas-fed PPTs and they utilized conventional gas dynamics subroutines to account for the plasma current sheet motion. Such models are not applicable to solid PPTs where the initial breakdown takes place in vacuum and the current sheet develops within evaporating plume. Modelling of the surface ablation and gas expansion into vacuum requires a solution of kinetic equations which in turn affects ionization kinetics modelling within the expanding plasma. Models of such level of complexity have been used for other applications (e.g. inertia fusion devices) but never been applied for development of space propulsion units. The key aspects of this modelling is to explain: 1) how the plasma is formed from the ablated material 2) how the moving current sheet attaches at the electrodes 3) how the geometry of the current sheet changes as plasma electrons tends to diffuse away
The novelty of the project is in the approach to the plasma modelling, in particular in allowing for a non-equilibrium distribution for the electrons, examining the emission of electrons from the cathode together with current attachment at the cathode and erosion of anode, propellant ablation and non-uniform distribution of electrons density in the current sheet, which have never been investigated before and the effects that these will have on the overall optimisation of the performance using the numerical tool. At the end of the project parametric studies will be performed in an attempt to arrive at optimized design solutions for small PPTs with different propellant configuration. The potential applications include propulsion units for micro- and nano- satellites. The project is related to physics of electric discharges and plasma phenomena. As such, applications would be welcome from candidates holding good degrees (1st class or 2:1 honours) in physics, materials science, engineering or applied mathematics. The project focus is mainly on theoretical (modelling) work but it may include some experimental research for models verification. Strong theoretical and numerical analysis skills are required. Previous experience in finite differences and finite element analyses of diffusion-convection problems would be an advantage.
If you wish to discuss any details of the project informally, please contact Dr Igor Golosnoy, Email: [email protected], or Prof Stephen Gabriel, Email: [email protected], EEE research group.