Hydroxylammonium nitrate

Abstract: Binary aqueous hydroxylammonium nitrate (HAN: [NH 3 OH] + [NO 3 ] − ) and hydrazinium nitroformate (HNF: [N 2 H 5 ] + [C(NO 2 ) 3 ] − ) have been prepared, then thermally and catalytically decomposed. The HAN solutions were prepared with different concentrations (20, 40, 79 wt.%), whereas HNF solution contains is 40 wt.% due to its lower solubility limit (about 50 wt.%). The catalyst was prepared by impregnation of modified support (Si-modified alumina) with monometallic active phase precursor (platinum) and characterized by transmission electron microscopy, X-ray diffraction and chemisorption. The reactions were followed by thermal analysis and by using a constant volume batch reactor. This work shows the essential effect of the monopropellant concentration to determine the best formulation for an industrial application. Moreover, HAN laboratory made solutions are more efficient for catalytic decomposition due to the absence of stabilizer to inhibit the catalyst. The Pt(10%)/Al 2 O 3 Si + HAN 79% lab association shows lower decomposition temperatures (down to room temperature), larger reaction rates and leads to higher amount of gaseous products, giving the most efficient system. With the same catalyst, HNF solution gave lower performances than HAN solutions, suggesting that the catalyst needs to be improved for this oxidizer.

Abstract: Imidazole-based ionic liquids are investigated in terms of dual-mode chemical monopropellant and electrospray rocket propulsion capabilities. A literature review of ionic liquid physical properties is conducted to determine an initial, representative set of ionic liquids that shows favorable physical properties for both modes, followed by numerical and analytical performance simulations. The ionic liquids 1-butyl-3-methylimidazolium dicyanamide, 1-butyl-3-methylimidazolium nitrate, and 1-ethyl-3-methylimidazolium ethyl sulfate meet or exceed the storability properties of hydrazine, and their electrochemical properties indicate that they may be capable of electrospray emission in the purely ionic regime. These liquids are projected to have 13–23% reduced monopropellant propulsion performance in comparison to hydrazine due to the prediction of solid carbon formation in the exhaust. The use of these ionic liquids as a fuel component in a binary monopropellant mixture with hydroxylammonium nitrate shows a 1–4...

Abstract: Analytical and numerical investigations of the performance of a series of potential dual-mode propulsion systems using ionic liquids are presented. A comparison of the predicted specific impulse of ionic liquids with hydrazine and unsymmetrical dimethylhydrazine shows that ionic liquid fuels have a 3–12% lower specific impulse when paired with a nitrogen tetroxide oxidizer. However, when paired with hydroxylammonium nitrate oxidizer, the specific impulse of the ionic liquids is 1–4% lower than that of hydrazine and unsymmetrical dimethylhydrazine paired with nitrogen tetroxide. Analytical investigation of an electrospray electric propulsion system shows that ion extraction in the pure ion regime provides a very high specific impulse, outside the optimum range for potential missions. Results suggest a deceleration grid, a lower ion fraction, or emission of higher solvated states is required. Analysis of a dualmode ionic-liquid-propelled spacecraft shows that the electric propulsion component determines the overall feasibility comparedwith current technology. Results indicate that the specific power for an ionic liquid electrospray systemmust be at least 15 W=kg in order for a dual-mode ionic liquid system to compete with traditional hydrazine and Hall thruster technology.