Experimental investigation of ionic liquid mixtures for electrospray propulsion
"In recent years, there has been a dramatic increase in the number of small satellites (namely MicroSats, NanoSats, and CubeSats) in earth orbit; many of these are launched without propulsion systems. Multi-mode propulsion systems, capable of operating in either chemical or electric mode, have been proposed as attractive candidates for use in small satellites. Such systems are mass and volume optimal and flexible in terms of thrust requirements. Most previous work on multi-mode systems has focused on chemical mode performance.The work in this dissertation focuses on the electric mode performance of these propulsion systems. The work in this research is comprised of three separate but related technical papers, each adding insight into the characterization and design of the electrospray (electric) mode of multi-mode propellant systems. The first paper focuses on determining species in the electrospray plume of a specific propellant, composed of 1-ethyl-3-methylimidazolium ethylsulfate ([Emim][EtSO4]) and hydroxylammonium nitrate (HAN), previously optimized for chemical mode performance. This paper shows HAN, a common energetic component, is present in the plume. The second paper identifies how changes in ionic liquid (IL) mixture ratio affects the species present in the plume and shows clear variations in plume species with mixture ratio for [Emim][EtSO4] and ethylammonium nitrate mixtures. The last paper quantifies how non-linearity in physical properties within IL mixtures impacts propellant performance. Predictions assuming linear mixing of properties over-predict emission current and thrust by up to 45% and 20%, respectively, when compared to calculations based on experimental mixture data"--Abstract, page iv.
Electrospray, Ionic Liquid Mixtures, Multi Mode, Propellant, Propulsion, Space craft, Aerospace Engineering
Missouri University of Science and Technology
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