Flame acceleration in the early stages of burning in tubes

• Acceleration of premixed laminar flames in the early stages of burning in long tubes is considered. The acceleration mechanism was suggested earlier by Clanet and Searby [Combust. Flame 105 (1996) 225]. Acceleration happens due to the initial ignition geometry at the tube axis when a flame develops to a finger-shaped front, with surface area growing exponentially in time. Flame surface area grows quite fast but only for a short time. The analytical theory of flame acceleration is developed, which determines the growth rate, the total acceleration time, and the maximal increase of the flame surface area. Direct numerical simulations of the process are performed for the complete set of combustion equations. The simulations results and the theory are in good agreement with the previous experiments. The numerical simulations also demonstrate flame deceleration, which follows acceleration, and the so-called '' tulip flames.'' (c) 2007 Published by Elsevier Inc. on behalf of The Combustion Institute.

Subject headings

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering (hsv//eng)

Keyword

NONSLIP

NUMERICAL-SIMULATION

simulations

direct numerical

DYNAMICS

WEAKLY TURBULENT

flame acceleration

VELOCITY

HYDRODYNAMIC INSTABILITY

CYLINDRICAL-TUBES

premixed flames

CURVED FLAMES

tulip flames

DETONATION

WALLS

Publication and Content Type

art (subject category)

ref (subject category)