Electronically Driven Combustion of Energetic Ionic Liquids in a Microcell Reactor

Area of Science:

• Plasma Science
• Combustion Chemistry
• Materials Science

Background:

• Energetic ionic liquids are promising green monopropellants.
• Understanding plasma-assisted combustion mechanisms is crucial for their development.
• Existing methods for studying these reactions are limited in throughput and diagnostic capabilities.

Purpose of the Study:

• To present a novel microcell reactor platform for investigating electronically driven combustion of energetic ionic liquids.
• To enable controlled ignition and characterization of intermediate species during plasma-assisted decomposition.
• To differentiate between thermal and plasma-driven combustion processes.

Main Methods:

• Utilized a microcell reactor platform with nanosecond pulsed plasma discharges.
• Employed a fuel mixture of 1-ethyl-3-methylimidazolium ethyl sulfate ([EMIM]-[EtSO4]) and hydroxylammonium nitrate (HAN).
• Applied optical emission spectroscopy and Raman shift thermometry for in situ diagnostics.

Main Results:

• Successfully controlled ignition and characterized intermediate species (CN, C2, N2, H, N) during plasma-assisted decomposition.
• Differentiated between thermally and plasma-driven combustion processes using spectroscopy and thermometry.
• Observed higher temperature shifts in the HAN + [EMIM]-[EtSO4] mixture due to pulsed plasma excitation.

Conclusions:

• The microcell reactor platform offers a high-throughput approach for advancing green monopropellant research.
• The study provides insights into plasma-assisted reaction mechanisms in energetic ionic liquids.
• The developed platform facilitates rapid testing of fuel variations and dopant effects for combustion enhancement.