Electrode degradation in micro-hollow cathode discharge reactors

This thesis presents an experimental study to understand the effects of different working fluids, flow rate, reactor hole diameter and dielectric thickness on the electrode degradation rate and total reactor lifetime of micro-hollow cathode discharge reactors. Oxidizing mediums such as air and carbon dioxide tend to degrade the reactors at a higher rate than non-oxidative mediums. Furthermore, larger dielectric thicknesses and smaller working fluid rates serve to decrease degradation. The overall longest reactor lifetime was accomplished at maximum diameter, thickness and minimum flowrate, resulting in a total lifetime of 14 hours 42 minutes. Additionally, creation of favorable magnetic fields through the use of nickel mesh electrodes was investigated in an attempt to increase the reactor lifetime. The results showed that the use of mesh electrodes decreased the total lifetime due to the higher energy plasma regime of the experimental reactors when compared to reactors found in the literature. Finally, the feasibility of utilizing MHCD reactors for oxygen production on a sample return mission to Mars was conducted. The study indicated that production quotas can be met but reactor lifetimes and power efficiency needed to be improved.