Improved Ignition Devices for 90% Hydrogen Peroxide/Polyethylene Hybrid Rocket Engine

Abstract

The stable ignition device is crucible to the rocket engine system especially for utilizing highly stabilized 90% hydrogen peroxide (HP) as an oxidizer. Generally, ignition of HP rocket expecting auto ignition by high temperature HP decomposition products with fuel though, the decomposition of highly stabilized HP is imperfect and auto ignition very uncertain due to the accumulated stabilizer in concentration process act as suppressor of decomposition. And addition, currently utilized active decomposition catalyst, modified 3way catalyst latent steam explosion danger. As ignition occur once successive combustion is stably sustained with direct injection of HP spray, liquid rocket igniter torch without decomposition catalyst is possible as long as there obtained hypergolic fuel with HP spray. Potassium permanganate (KMnO4) loaded fuels used for the purpose with assistance of igniter plug. In order to find oxidizer mass flux for sustaining hybrid rocket combustion, large fuel length/burning port diameter ratio (L/D=35) transparent polymethylmetacrylate (PMMA) solid fuel small hybrid rocket studies also have been carried out. The oxidizer mass flux has to be over the flux that extend diffusion flame up to the aft end of the solid fuel. The required minimum oxidizer mass flux was confirmed for the multi perforation solid fuel grain. Honeycomb arranged multi hexagonal perforation for low regression rate large engine and multi spoke wagon wheel for low regression rate small size or high regression rate large scale engine solid fuel grain designs are preferable.