Flame propagation through turbulent combustible dust/air mixtures

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5537872

Tezok, F I

Propagation of turbulent dust/air flames was studied experimentally. Measurements of the burning velocity were made in a 0.95 m/sup 3/ spherical chamber using the constant volume bomb technique. Mixture concentration was constantly monitored before the explosion by an optical dust probe, and turbulence was created by six symmetrically located inlet jets. The turbulence level inside the chamber was adjusted by the inlet jet velocities. Steady state conditions were established before simultaneous isolation and ignition. Burning velocities of 45-100 cm/sec and 70-330 cm/sec were obtained for mixed grain dust and cornstarch respectively for controlled moisture, particle size distribution, and turbulence level (1.5-4.2 m/sec-rms) for a dust concentration range of 50-1300 gm/m/sup 3/. The maximum pressure and rate of pressure rise data showed general agreement with other sources (K/sub ST/ = 71 bar sec/sup -1/ m). The ratio of turbulent to laminar burning velocity was found to correlate well with both the ratio of rms turbulent fluctuation velocity to laminar burning velocity ratio and Reynolds number. Measurements and calculations strongly suggest that the propagation of the flame, for high turbulence levels, is controlled by turbulent exchange, whereas for low turbulence intensities it is probably controlled by radiation, which causes prior pyrolysis, and most of the combustibles burn in the gas phase.

• Research Organization: Michigan Univ., Ann Arbor (USA)
• OSTI ID: 5537872
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
AIR
COMBUSTION
FLAME PROPAGATION
DUSTS
EXPLOSIONS
MIXTURES
PARTICLE SIZE
TURBULENCE
VELOCITY
CHEMICAL REACTIONS
DISPERSIONS
FLUIDS
GASES
OXIDATION
SIZE
THERMOCHEMICAL PROCESSES
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry
450100 - Military Technology
Weaponry
& National Defense- Chemical Explosions & Explosives