Freely propagating open premixed turbulent flames stabilized by swirl
- Hong Kong Polytechnic, Kowloon (Hong Kong)
- Lawrence Berkeley Lab., CA (United States)
A novel means has been developed for using weak swirl to stabilize freely propagating open premixed turbulent flames (swirl numbers between 0.05 to 0.3). By injecting a small amount of air tangentially into the co-flow of a concentric burner, stationary flames can be maintained above the burner exit for a large range of mixture, turbulence and flow conditions. The absence of physical surfaces in the vicinity of the flame provides free access to laser diagnostics. Laser Doppler anemometry and laser Mie scattering measurements of four flames with and without incident turbulence show that their features are typical of wrinkled laminar flames. The most distinct characteristics is that flame stabilization does not rely on flow recirculation. Centrifugal force induced by swirl causes flow divergence, and the flame is maintained at where the local mass flux balances the burning rate. The flame speeds can be estimated based on the centerline velocity vector, which is locally normal to the flame brush. This flame geometry is the closest approximation to the 1-D planar flame for determining fundamental properties to advance turbulent combustion theories. 18 refs.
- Research Organization:
- Lawrence Berkeley Lab., CA (United States); Hong Kong Polytechnic, Kowloon (Hong Kong)
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 7206972
- Report Number(s):
- LBL-31581; CONF-9203140--3; ON: DE92017116
- Country of Publication:
- United States
- Language:
- English
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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
AIR
ALKANES
ALKENES
ANEMOMETERS
DISPERSIONS
ETHYLENE
FLAME PROPAGATION
FLAMES
FLUID FLOW
FLUIDS
GASES
HYDROCARBONS
LAMINAR FLOW
LASER DOPPLER ANEMOMETERS
MEASURING INSTRUMENTS
METHANE
MIXTURES
ORGANIC COMPOUNDS
TURBULENT FLOW
VORTEX FLOW