INVESTIGATION OF SOLID OXIDIZER AND GASEOUS FUEL COMBUSTION PERFORMANCE USING AN ELEVATED PRESSURE COUNTERFLOW EXPERIMENT FOR REVERSE HYBRID ROCKET ENGINE

摘要

Pressurized counterflow burner and static-fired motor studies were conducted to explore the possibility of a reverse hybrid system, having a solid oxidizer and gaseous fuel. Theoretical performance analysis indicates such a system may yield specific impulse and density specific impulse similar to composite solid propellants. Pressurized counterflow flame studies, conducted using pressed ammonium perchlorate (AP) pellets and gaseous ethylene, show three pressure dependent combustion regimes. AP decomposition, for pressures below 1 MPa, is controlled by heat transfer from the resulting diffusion flame, which forms between the fuel and decomposition products ofAP. In this low pressure regime, the AP burning rate is found to increase with flame strain rate and pressure, yielding measured values between 0.1 to 0.5 mm/s. As pressure increases, the monopropellant flame moves closer to the oxidizer surface until the pressure reaches the self-decomposition limit, at which point the monopropellant flame becomes nearly independent of the diffusion flame. Further increasing the pressure yields burning rates between 0.4 to 0.7 cm/s, which are consistent with the literature. Variation of flame strain rate under these conditions has little or no influence on the AP burning rate for the range of flow conditions tested. Similar studies conducted with methane suggest burning rates are unaffected by fuel type. Lab-scale static motor firings were conducted to examine ignition, variation of fuel flow rate and initial motor pressure, and system performance. Results indicate that successful motor operation requires initial pressures capable of boosting the system into the higher burning rate regimes.