Spectral behavior of velocity fluctuations in premixed turbulent flames

Journal Article · Mon Feb 29 23:00:00 EST 1988 · Combust. Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(88)90066-1· OSTI ID:7002329

Gokalp, I; Shepherd, I G; Cheng, R K

The characteristics of the velocity spectra of two ethylene/air premixed turbulent v-flames have been studied. The spectral data are used to compare the response of two chemically similar flames to different approach flow turbulent structures. The velocity measurements are made using a single component laser Doppler anemometry system, and the velocity spectra for the velocity components 30/sup 0/ to be normal of the flame are deducted. Also deducted are the spectral distribution in wave-number space, the integral time, and length scales. The spectra show that the influences of the turbulent flames on spectral behavior do not correlate strongly with the turbulence Reynolds number and that criteria, such as the Damkohler number, which describe the flame/turbulence interaction must be considered. The wave-number spectra show clearly the shifting of the energy containing eddies to lower frequencies in the product zone. The shifting to lower frequencies is consistent with the dilation effect due to the increase in temperature and viscosity. The dilation effects are also apparent in the integral length scales profiles. Marked differences in the flame response are evident in the evolution of the spectral slopes and integral time scales through the flames and increases in the velocity fluctuations within the flame zone. These differences suggest that the passage frequencies of the wrinkled turbulent flame front may be important for the interpretation of velocity spectra.

• Research Organization: CRCCHT-CNRS, 45071 Orleans (FR)
• OSTI ID: 7002329
• Journal Information: Combust. Flame; (United States), Journal Name: Combust. Flame; (United States) Vol. 71:3; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
AIR
ALKENES
ANEMOMETERS
CHEMICAL ANALYSIS
ETHYLENE
FLAME PROPAGATION
FLAMES
FLOW RATE
FLUID MECHANICS
FLUIDS
GASES
HYDROCARBONS
HYDRODYNAMICS
MEASURING INSTRUMENTS
MECHANICS
METERING
ORGANIC COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
REYNOLDS NUMBER
SPECTRA
TURBULENCE