Lessons learned from the development and testing of the novel green hypergolic propellant HIP_11

Kurzfassung

This paper gives an overview on the development of the alternative propellant HIP_11 and provides some lessons learned during the development. HIP_11 is a hypergolic combination consisting of hydrogen peroxide and an ionic liquid based fuel. The combination was developed in the frame of Lauck’s PhD project. The development was conducted in several steps: the identification of potential fuels, the initial screening of hypergolicity in lab scale drop test, the verification of the hypergolic ignition under relevant conditions and the evaluation of the performance in tests with a battleship thruster. The lessons learned during the different steps of the development include: In drop tests the order of drops has a high influence on the ignition delay. For drop tests with a fuel pool and a H2O2 drop the ignition delay is significantly shorter than vice versa. Rapid unexpected decomposition events occurred in the injection tests. These event lead to high pressure peaks in the H2O2 feeding line. These events were related to the presence of H2O2 vapour present in the feeding lines. Initial tests with different battleship combustion chambers proved the suitability of HIP_11 for the use in a rocket engine and the possibility of a smooth hypergolic ignition.