Burning velocities and flammability limits of gaseous mixtures at elevated temperatures and pressures

Journal Article · Fri Sep 01 04:00:00 EDT 1995 · Combustion and Flame

DOI:https://doi.org/10.1016/0010-2180(95)00002-N· OSTI ID:116444

Shebeko, Y N; Tsarichenko, S G; Korolchenko, A Y; Trunev, A V; Navzenya, V Y; Papkov, S N; Zaitzev, A A ^[1]

---

1. All Russian Scientific Research Institute for Fire Protection, Balashiha (Russian Federation)

Burning velocities and flammability limits of gaseous mixtures of combustible gas (hydrogen and methane), oxidizer (oxygen and air), and diluent (nitrogen, argon, helium, carbon dioxide, steam, water aerosol formed by evaporation of superheated water) have been measured at elevated temperatures (up to 250 C) and pressures (up to 4.0 MPa). It was found that with increasing temperature, the flammability region is widened for all mixtures studied. With increasing pressure,t eh flammable region for mixtures of hydrogen-oxygen-diluent is narrowed, except where steam or water aerosol is the diluent. A more complicated dependence of flammability limit on pressure is found for mixtures of hydrogen-oxygen-steam. The influence of water aerosol on the flammability limits of methane in air was also investigated. It was found that the inertia action of such an aerosol is mainly due to the stem available within it. The dependences of burning velocity on temperature and pressure were investigated for stoichiometric hydrogen-air mixtures diluted by nitrogen and steam. It has been shown that, over the ranges of temperature and pressure considered, the temperature index of burning velocity is positive, while the pressure index changes sign from positive to negative on dilution by inert agents. The observed differences in the influences of steam and nitrogen on burning velocity cannot be explained on the basis of a thermal mechanism alone and is mainly due to the more active role of water molecules in enhancing termolecular recombination reactions in the flame front. The influence of small quantities of methane on the burning velocity of hydrogen-air mixtures also was investigated.

• OSTI ID: 116444
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 4 Vol. 102; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
08 HYDROGEN
40 CHEMISTRY
COMBUSTION KINETICS
DETONATION LIMITS
FLAMMABILITY
FUEL-AIR RATIO
HYDROGEN
METHANE
MIXTURES
PRESSURE DEPENDENCE
TEMPERATURE DEPENDENCE