Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published October 2000 | Accepted Version
Journal Article Open

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


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 have been determined and the influence of small amounts of oxygen on the flammability of methane–nitrous oxide–nitrogen mixtures has been investigated. Flame speeds have been measured and laminar burning velocities have been 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: H₂–N₂O: 4.5 ∼ 5.0% H₂(LFL), 76 ∼ 80% H₂(UFL); CH₄–N₂O: 2.5 ∼ 3.0% CH₄(LFL), 43 ∼ 50% CH₄(UFL); NH₃–N₂O: 5.0 ∼ 5.2% NH₃(LFL), 67.5 ∼ 68% NH₃(UFL). Inerting concentrations are: H₂–N₂O–N₂: 76% N₂; CH₄–N₂O–N₂: 70.5% N₂; NH₃–N₂O–N₂: 61% N₂; NH₃–N₂O–air: 85% air. Flammability limits of methane–nitrous oxide–nitrogen mixtures show no pronounced dependence on small amounts of oxygen (<5%). Generally speaking, flammable gases with large initial amounts of nitrous oxide or ammonia show a strong dependence of flammability limits on ignition energy.

Additional Information

© 2000 The Combustion Institute. Published by Elsevier Inc. Received 1 February 1999, Revised 29 March 2000, Accepted 6 April 2000, Available online 14 September 2000. This work was supported by the U.S. Department of Energy under contract 929Q0015-3A, DOE W-7405-ENG-36. We thank Jerry Johnson for the support.

Attached Files

Accepted Version - flimits.pdf


Files (415.2 kB)
Name Size Download all
415.2 kB Preview Download

Additional details

August 19, 2023
October 20, 2023