Experimental analysis of flamelet models for premixed turbulent combustion

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:93276

Veynante, D; Duclos, J M; Piana, J ^[1]

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1. Ecole Centrale Paris, Chatenay-Malabry (France)

Flamelet models are now widely used to predict turbulent premixed combustion because they allow the separation of chemical features from the description of the turbulent flow field. Some of them introduce a flame surface density (flame surface per unit volume) modelled either by an algebraic closure (Bray-Moss-Libby model) or from a transport equation. This equation may be exactly written but needs closure assumptions. In the present work, a two-dimensional turbulent premixed propane-air V flame is studied. Velocity profiles are obtained from laser-Doppler velocimetry. Flame front visualizations are achieved by tomography with high-speed cinematography using a copper vapor laser. Images are then processed to extract flame front characteristics (flame surface density, vector normal to the flame front, curvature). The Bray-Moss-Libby model is found to have a good trend but needs a precise closure of the flame wrinkling length scale. Then some terms of the exact transport equation for flame surface density are examined. A simple model is proposed to close the strain rate term acting on the flame surface and due to the mean flow. Curvature and propagation terms are found to act as a source term on the fresh gases side and as a consumption term on the burnt one. This fact points out a lack in the generally used closures of the flame surface density equation where the propagation term is neglected and the curvature term modelled as a destruction one.

• OSTI ID: 93276
• Report Number(s): CONF-940711--
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
COMBUSTION KINETICS
COMBUSTION WAVES
EXPERIMENTAL DATA
FLAME PROPAGATION
FLAMES
FLOW RATE
FLOW VISUALIZATION
MATHEMATICAL MODELS
MORPHOLOGY
PROPANE
TURBULENT FLOW
ULTRAHIGH-SPEED PHOTOGRAPHY