Hypergolic ignition behaviors of green propellants with hydrogen peroxide: The TMEDA/DMEA system

Abstract

For nearly-six decades, hydrazine and its derivatives have been the standard fuels for rockets and spacecrafts. However, their attractive features are offset by their toxicity and associated high handling and storage costs. This work presents a novel green fuel system based on N,N,N’N’-Tetramethylethylenediamine (TMEDA), dimethylaminoethanol (DMEA) and methanol or ethanol with high test peroxide (HTP). Drop tests were performed with 27 samples using both high speed photography and transient infrared imaging. Results have shown that neither pure TMEDA nor pure DMEA is hypergolic with high test peroxide (HTP) even with copper chloride (anhydrous or hydrated) as the catalyst. Interestingly, their combination provided a synergistic effect achieving hypergolic behavior with a consistently low ignition delay time (IDT) using only half a percent of catalyst, and the near-optimal hypergolic ignition behavior was achieved with a volume ratio of TMEDA to DMEA of 50:50. In addition, in order to adjust some properties of this blend, TMEDA/DMEA (50:50) was further mixed with methanol or ethanol with different ratios and they showed even better hypergolic ignition performance with IDT as low as 10 ms. Besides their good hypergolic ignition performance characteristics, these new fuel systems based on two propagators (TMEDA/DMEA) and a solvent (methanol or ethanol) also present low viscosity and comparable theoretical specific impulses compared to the conventional hydrazine-based systems. It is believed that this catalytically promoted hypergolic systems with HTP open up a new avenue to the replacement of conventional highly toxic hypergolic propellants.