Combustion enhancement of a premixed flame by acoustic forcing with emphasis on role of large-scale vortical structures

Conference · Tue Jan 01 00:00:00 EST 1991

OSTI ID:6170151

Yu, K; Trouve, A; Candel, S ^[1]

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1. Naval Weapons Center, China Lake, CA (USA) Stanford Univ., CA (USA) Ecole Centrale des Arts et Manufactures, Chatenay-Malabry (France)

The response of a chemically reacting, turbulent shear flow subject to flow excitation is studied in a two-dimensional, laboratory combustor. The combustor employs a V-shaped bluff-body flame holder. A premixed propane-air mixture flows over the flame holder creating two turbulent mixing layers, in which combustion is initiated. The inlet flow is periodically surged by acoustically forcing the upstream flow and the flame response is investigated in the near wake region behind the stabilizer. Experimental observations combine acoustic pressure measurements, C2 radical spectroscopy, and direct-shadow spark visualization. It is shown that forcing may produce significant increases in overall combustion rate by generating periodic large-scale vortical structures. These orderly structures accelerate the entrainment and improve the mixing between incoming fresh reactants and recirculating hot gases. The magnitude of the increase is a sensitive function of forcing frequency. Data indicate that maximum combustion enhancement occurs when the forcing frequency matches the preferred mode of the hydrodynamic field in the near wake region. 13 refs.

• OSTI ID: 6170151
• Report Number(s): AIAA-Paper-91-0367; CONF-910117-
• Resource Relation: Conference: 29. AIAA aerospace sciences conference, Reno, NV (USA), 7-10 Jan 1991
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PROPANE
COMBUSTION KINETICS
CHEMICAL REACTIONS
COMBUSTION CHAMBERS
FLAMES
FLOW VISUALIZATION
FLUID FLOW
FORCING FUNCTIONS
FUEL-AIR RATIO
MIXING
SHEAR
TURBULENT FLOW
VORTICES
ALKANES
CHEMICAL REACTION KINETICS
HYDROCARBONS
KINETICS
ORGANIC COMPOUNDS
REACTION KINETICS
400800* - Combustion
Pyrolysis
& High-Temperature Chemistry