Velocity statistics in premixed turbulent flames

Journal Article · Sat Jan 01 04:00:00 EST 1983 · Combust. Flame; (United States)

DOI:https://doi.org/10.1016/0010-2180(83)90131-1· OSTI ID:5892027

Cheng, R K; Ng, T T

Laser Doppler velocimetry was used to measure velocity statistics in six unconfined v-shaped premixed ethylene/air turbulent flames with incident turbulence generated by grid or perforated plate. Also obtained were high speed schlieren movies of the turbulent flames. The results discussed include two components of mean and rms velocities, probability density functions, macroscales, and Reynolds stress. In most cases, turbulent intensities increase within the flame zone. This increase is attributed to the intermittent measurement of the flow velocities in the burned and unburned states as the thin flame sheet fluctuates about the stationary measurement point. Reynolds stress also increases in the flame zone, but its sign suggests removal of turbulent kinetic energy. Therefore, conventional gradient transport modeling would break down for these flames. The sign of the Reynolds stress is in qualitative agreement with contributions due to intermittent measurement of the turbulent components in the burned and unburned states. These results show that the intermittency effect is a major influence on turbulent statistics in premixed flames and should require careful consideration in numerical models.

• Research Organization: Univ. of California, Berkeley
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5892027
• Journal Information: Combust. Flame; (United States), Journal Name: Combust. Flame; (United States) Vol. 52; ISSN CBFMA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALKENES
CHEMICAL REACTIONS
COMBUSTION
ETHYLENE
FLAMES
FLUID FLOW
FUEL-AIR RATIO
HYDROCARBONS
ORGANIC COMPOUNDS
OXIDATION
THERMOCHEMICAL PROCESSES
TURBULENT FLOW
VELOCITY