Hybrid rocket systems have the potential to high performance and wide operational capabilities, as well as throttling and shutdown. An essential component in any rocket system is the ignition mechanism. This can allow the motor to initiate proper burning, as well as provide ignition – shutdown- re-ignition capabilities. Currently, the ignition of hybrid motors is generally achieved by the addition of external gas or liquid systems, or by a consumable catalytic bed (CCB), resulting in more complex and heavy systems.
In the present work, a hypergolic hybrid rocket motor is proposed to obtain a more efficient hybrid propulsion system. The hypergolic ignition proposed, i.e., ignition of the fuel upon contact with the oxidizer, allows very short ignition delay times and shutdown – re-ignition capabilities without any need of external systems that add weight, length and complexity to the system. The hypergolic ignition is achieved by embedding a catalyst, or promoter, which is hypergolic with the liquid oxidizer, into the solid grain. The hypergolic reaction between catalyst and oxidizer is highly exothermic, and enough, to cause the ignition and combustion of the solid fuel together with the liquid oxidizer. In the present work, different catalysts and fuels were tested with high concentration hydrogen peroxide via drop-on-solid tests and radial injection, to prove the feasibility of such ignition.
The idea of hypergolic ignition between a solid fuel and a liquid oxidizer was proven under different ambient conditions for different fuels. Average ignition delay times in the tests performed were always less than 10 ms, depending on the fuel and catalyst load in the solid grain.
