Transfer function characteristics of bluff-body stabilized, conical V-shaped premixed turbulent propane-air flames

Journal Article · Sat Apr 15 04:00:00 EDT 2006 · Combustion and Flame

DOI:https://doi.org/10.1016/j.combustflame.2005.10.013· OSTI ID:20727306

Chaparro, Andres; Landry, Eric; Cetegen, Baki M ^[1]

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1. Mechanical Engineering Department, University of Connecticut, 191 Auditorium Road, Storrs, CT 06269-3139 (United States)

The response of bluff-body stabilized conical V-shaped premixed flames to periodic upstream velocity oscillations was characterized as a function of oscillation frequency, mean flow velocity, and equivalence ratio. The flame heat release response to the imposed velocity oscillations was determined from the CH* chemiluminescence captured by two photomultiplier (PMT) detectors at a wavelength of 430 nm. One of the PMTs viewed flame radiation in a 10-mm horizontal slice, 50 mm above the bluff-body. The second PMT observed the overall flame radiation. The flame transfer function characteristics were determined from the spectral analysis of the velocity and PMT signals. It was found that the flame heat release amplitude response is confined to low-frequency excitation below a Strouhal number of 4. The phase relationship of the transfer function for these turbulent flames was evaluated using the signal from the spatially masked PMT. The transfer function estimate based on these data exhibits second-order characteristics with a phase lag between the velocity and heat release signals. The localized heat-release response contains frequencies that are multiples of the excitation frequency, suggesting splitting and tilting of flame structures as well as some nonlinear effects. Increase of flame equivalence ratio from lean toward stoichiometric resulted in slight amplification of the high-frequency response. (author)

• OSTI ID: 20727306
• Journal Information: Combustion and Flame, Journal Name: Combustion and Flame Journal Issue: 1-2 Vol. 145; ISSN CBFMAO; ISSN 0010-2180
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
42 ENGINEERING
AIR
COMBUSTION KINETICS
COMBUSTORS
FLAMES
GAS TURBINES
OSCILLATIONS
PROPANE
TURBULENCE
VELOCITY