Authors: S. J. Volchko, C. J. Sung, Y. Huang, and S. J. Schneider

Direct link to the paper: 20814, 35400011544054.0250

Abstract:

In an effort to aid the development of micropropulsion devices with a thrust level of 1-10 mN, as required by the next generation of miniaturized satellites and spacecraft, the combustion of rich methane/oxygen propellant mixtures in platinum microtubes with inside diameters of 0.4 and 0.8 mm is characterized. All of the mixtures tested had equivalence ratios beyond the corresponding rich flammability limits. Experimental results show that catalytic reactions could support combustion in mixtures even when gas-phase chemistry does not play a significant role. The effects of varying equivalence ratio, pressure, mass flow rate, and tube diameter on the critical temperature leading to catalytic ignition are systematically investigated. Furthermore, the effects of doping the methane/oxygen mixture with hydrogen are explored, demonstrating a substantial reduction in the ignition temperature with hydrogen addition. Microtube performance in terms of available thrust, specific impulse, and power required for preheating the microtube are also discussed. By the use of a plug flow model, the experimental conditions are simulated with detailed gas-phase/surface chemistry, thermodynamic properties, and transport properties. The computational results generally support the experimental findings.

Citation: S. J. Volchko, C. J. Sung, Y. Huang, and S. J. Schneider, “Catalytic Combustion of Rich Methane/Oxygen Mixtures for Micropropulsion Applications,” Journal of Propulsion and Power 22 (3), 684-693 (2006).