Characterization of Pintle Engine Performance for Nontoxic Hypergolic Bipropellants

Using rocket grade hydrogen peroxide (RGHP) and a nontoxic, hypergolic miscible fuel (NHMF), a 150-lbf thrust class pintle injector engine has been developed at Purdue University for the purposes of determining parameters leading to high combustion efficiency. The parameters investigated include characteristic length, chamber diameter-to-pintle diameter ratio, total momentum ratio (TMR), secondary-to-primary hole diameter ratio, and the pintle length-to-pintle diameter ratio. High performance has been achieved in both steady-state and pulse mode operation. Nomenclature RGHP Rocket grade hydrogen peroxide NHMF Nontoxic, Hypergolic, Miscible Fuel TMR Total Momentum Ratio NTO Nitrogen tetroxide MMH Monomethyl hydrazine TMR Total Momentum Ratio ISP Specific impulse ISPv Vacuum Specific Impulse ρISPv Vacuum density specific impulse PC Chamber pressure ∈ Nozzle area ratio DSEC Secondary hole diameter DPRI Primary hole diameter L* Characteristic length c* Characteristic velocity sps Samples per second fps Frames per second