Hot Firing Tests of a Novel Green Hypergolic Propellant in a Thruster

Abstract

This study investigates the ignition and combustion behavior of the recently developed green hypergolic combination named HIP_11 in a small thruster. The combination HIP_11 consists of highly concentrated hydrogen peroxide as oxidizer and a fuel based on the ionic liquid 1-ethyl-3-methylimidazolium thiocyanate (EMIM SCN) with addition of copper thiocyanate (Cu SCN) to facilitate the hypergolic ignition. A dedicated thruster, featuring a 2-on-1 unlike impinging jet injector, was designed and manufactured. The initial tests were conducted with the injector only, without the combustion chamber mounted. These tests were conducted with two different amounts of catalyst: 1% and 5% Cu SCN. Subsequently, three hot firing series (around 35 tests) were conducted with the complete thruster, using the propellant combination 97% high-test peroxide and EMIM SCN+5% Cu SCN. The propellant mass flow rates were varied between 7 and 13  g/s and the oxidizer-to-fuel ratio from 3 to 7.