Optical Properties of the Hypergolic Reaction Between Green Ionic Liquids and Highly Concentrated Hydrogen Peroxide

Abstract

The hypergolic reaction between the recently developed green propellant combination consisting of an ionic liquid and highly concentrated hydrogen peroxide was investigated for several ratios of oxidizer and fuel, drop sizes and heights of fall. The influence of the catalytic copper additive on the ignition delay time (IDT) was analysed. Flame emission/absorption spectroscopy revealed the chemical constituents. All spectra were dominated by sodium D-lines at λ= 589nm. Further lines of alkali metals such as lithium and potassium were found. The copper additive showed its characteristic lines accordingly to its amount in the fuel. Emission spectra of the ultraviolet regime showed the characteristic OH* molecular lines around λ= 306nm with its temperature dependent intensity ratios [1][2]. The catalytic additive copper increases the flame temperature while it decreases the IDT from 31 ms for pure ionic liquid to 15 ms (5% mass fraction).