ETD

• electric propulsion
• naphthalene propellant
• radio-frequency gridded ion thrusters
• ZDPlasKin
• zero-dimensional thruster model

This thesis investigates naphthalene as solid propellant for electric space propulsion, focusing on the development of a zero-dimensional global model for radiofrequency gridded ion thrusters.
The primary objective is to develop a computational framework simulating the plasma chemistry and performance of naphthalene-fed RF thrusters. The model incorporates 79 chemical species-electrons, neutral naphthalene and fragments and positive ions-with a total of 625 reactions including electron-impact processes, ion-molecule reactions, and neutral-neutral interactions.
Electron-impact cross sections are derived using a combined theoretical-experimental approach. The Mass Spectrum Derived (MSD) method scales the total ionization cross section from Binary Encounter Bethe (BEB) calculations according to branching ratios from experimental mass spectrometry data, representing naphthalene's complex fragmentation patterns.
The numerical implementation uses the ZDPlasKin framework for plasma kinetics simulations, coupled with the BOLSIG+ solver for the Boltzman equation and ODE solver DVODE.
The original ZDPlasKin module was modified and extended to incorporate transport phenomena specific to the thruster configuration, including propellant injection, wall diffusion, ion extraction through grids and convective transport.
An extensive parametric study analyzes how electron temperature, gas temperature, mass flow rate, grid voltage, and RF frequency influence thruster performance metrics.