Flammability limits, ignition energy, and flame speeds in H2-CH4-NH3-N2O-O2-N2 mixtures

• Published in: Combustion and flame Vol. 123; no. 1-2; pp. 140 - 158
• Main Authors: PFAHL, U. J, ROSS, M. C, SHEPHERD, J. E, PASAMEHMETOGLU, K. O, UNAL, C
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Science 01.10.2000
• Subjects: Applied sciences; Combustion of gaseous fuels; Combustion. Flame; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Theoretical studies. Data and constants. Metering; Methane; Ammonia; Laminar flame; Hydrogen; Ignition; Combustion; Nitrogen protoxide; Flammability limit; Combustion velocity
• ISSN: 0010-2180; 1556-2921
• DOI: 10.1016/S0010-2180(00)00152-8

Experiments on flammability limits, ignition energies, and flame speeds were carried out in a 11.25- and a 400-liter combustion vessel at initial pressures and temperatures of 100 kPa and 295 K, respectively. Flammability maps of hydrogen-nitrous oxide-nitrogen, methane-nitrous oxide-nitrogen, ammonia-nitrous oxide-nitrogen, and ammonia-nitrous oxide-air, as well as lean flammability limits of various hydrogen-methane-ammonia-nitrous oxide-oxygen-nitrogen mixtures were determined. Ignition energy bounds of methane-nitrous oxide, ammonia-nitrous oxide, and ammonia-nitrous oxide-nitrogen mixtures are determined, and the influence of small amounts of oxygen on the flammability of methane-nitrous oxide-nitrogen mixtures is investigated. Flame speeds were measured, and laminar-burning velocities are determined for ammonia-air-nitrous oxide and various hydrogen-methane-ammonia-nitrous oxide-oxygen-nitrogen mixtures. Lower and upper flammability limits (mixing fan on, turbulent conditions) for ignition energies of 8 J are determined. Inerting concentrations are also established. Flammability limits of methane-nitrous oxide-nitrogen mixtures show no pronounced dependence on small amounts of oxygen (less than 5 percent). Generally speaking, flammable gases with large initial amounts of nitrous oxide or ammonia show a strong dependence of flammability limits on ignition energy. (Author)