Acceleration of a flame by flame-vortex interactions

Journal Article · Wed Oct 31 23:00:00 EST 1990 · Combustion and Flame; (USA)

DOI:https://doi.org/10.1016/0010-2180(90)90091-5· OSTI ID:5773738

Barr, P K ^[1]

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1. Sandia National Labs., Livermore, CA (USA). Combustion Research Faclity

The acceleration of a premixed flame propagating in a planar channel past stationary obstacles is investigated using a computer model based on combining the discrete vortex method with a flame interface algorithm. Results presented in this article show that the initial acceleration of the flame is caused by the sudden contraction of the flow due to the presence of the obstacles. Because the burning speed {ital S{sub L}} remains constant, it is the increase in surface area that is responsible for the apparent acceleration. This combustion-generated flow also causes turbulent recirculation regions to form downstream of the obstacles. When the flame interacts with these turbulent eddies, the burning rate increases, producing a stronger velocity field in the channel that further accelerates the flame. In geometries containing a series of obstacles, the higher flow velocities caused by the distorted flame result in stronger turbulent eddies behind subsequent obstacles. Numerical results for these geometries demonstrate the positive feedback mechanism of acceleration as the flame encounters these increasingly stronger turbulent regions. In this article, results are presented for different locations of the series of obstacles, as well as a clustering of obstacles near the ignition source. The effects of blockage ratio, ignition shape, and fuel concentration are also investigated with the computer model.

• OSTI ID: 5773738
• Journal Information: Combustion and Flame; (USA), Journal Name: Combustion and Flame; (USA) Vol. 82:2; ISSN CBFMA; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
42 ENGINEERING
420400 -- Engineering-- Heat Transfer & Fluid Flow
CHEMICAL REACTION KINETICS
COMBUSTION KINETICS
COMPUTERIZED SIMULATION
FLAME PROPAGATION
FLAMES
FLUID FLOW
FUELS
KINETICS
REACTION KINETICS
SIMULATION
TURBULENT FLOW