Abstract
Physical properties, performance metrics, and mass spectra of mixtures of two ionic liquids (1-ethyl-3-methylimidazolium ethyl-sulfate aka [Emim][EtSO4] and ethyl ammonium nitrate aka EAN) are investigated from the standpoint of electrospray propulsive characteristics. Spectra suggest that as the [Emim][EtSO4] mixture fraction increases, the intensity of [Emim][EtSO4] related species in the plume also increases, while the presence of EAN decreases. Spectra also show presence of both EAN proton transfer species and species related to chemical reaction of [EtSO4] and water. Despite the volatility of EAN, it emits stably into vacuum at low flow rates when mixed with 25% [Emim][EtSO4]. Spectra also show species swapping between [Emim][EtSO4] and EAN, suggesting microscopic reorganization and non-linear mixing of physical properties. Experimental measurements of surface tension, conductivity, and density for various mixture mass percentages also show non-linear mixing characteristics. Conductivity differs by over 40% from linear predicted values. Analytic predictions of propulsion performance are presented based on the nonlinear experimental property results and compared to predictions based on linear mixing models. Results indicate non-linear mixing is important when making performance predictions, with differences of at least 40% possible. Curve fits of experimentally determined properties of the mixtures versus mixture ratio can be used to determine maximum or minimum performances based on different performance metrics (current, thrust, and specific impulse); for these ionic liquids the metrics are shown to optimize at different mixture mass percentages, over a 2% range; this range will increase when mixing liquids with more disparate densities.
Recommended Citation
M. J. Wainwright et al., "Experimental Investigation of Mixtures of 1-Ethyl-3-Methylimidazolium Ethyl Sulfate and Ethylammonium Nitrate with Electrospray Propulsion Applications," AIAA Propulsion and Energy Forum and Exposition, 2019, American Institute of Aeronautics and Astronautics, Jan 2019.
The definitive version is available at https://doi.org/10.2514/6.2019-3900
Department(s)
Mechanical and Aerospace Engineering
Publication Status
Full Access
International Standard Book Number (ISBN)
978-162410590-6
Document Type
Article - Conference proceedings
Document Version
Citation
File Type
text
Language(s)
English
Rights
© 2024 American Institute of Aeronautics and Astronautics, All rights reserved.
Publication Date
01 Jan 2019
Comments
National Aeronautics and Space Administration, Grant NNM15AA09A