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Title: Stabilization of an unconfined flame by a bluff body

The study of turbulent combustion is motivated by the need for more-efficient use of fossil fuels. In particular, the stabilization region of an unconfined premixed turbulent flame on a bluff body is important as a fundamental and practical problem, for its implications for other stabilized flames and for its applications in turbojet afterburners. A detailed study of the velocity and density fields of an ethylene-air V-shaped flame in an open jet (50 mm diameter) wind tunnel with grid-generated turbulence was made. Two velocity components were measured simultaneously using Laser Doppler Anemometry. Point measurements of gas density were made non-intrusively using laser Rayleigh scattering. The development of the leading edge of the flame sheet was analyzed with an ionization probe. Only the richer flame stabilized, showing evidence of vortices shed in the wake. These did not, however, perturb the flame. Near the flame holder, the density and velocity probability density functions have monomodal distributions but further downstream these evolve into the bimodal shape characteristic of wrinkled laminar flames. This was found to be a useful stabilization criterion when comparing the various flames.
Authors:
Publication Date:
OSTI Identifier:
7246656
Resource Type:
Thesis/Dissertation
Resource Relation:
Other Information: Thesis (Ph. D.)
Publisher:
Univ. of California,Berkeley, CA
Research Org:
California Univ., Berkeley (USA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; COMBUSTION; FLAMES; TURBULENCE; ETHYLENE; STABILIZATION; AIR; DENSITY; MIXTURES; ALKENES; CHEMICAL REACTIONS; DISPERSIONS; FLUIDS; GASES; HYDROCARBONS; ORGANIC COMPOUNDS; OXIDATION; PHYSICAL PROPERTIES; THERMOCHEMICAL PROCESSES 400800* -- Combustion, Pyrolysis, & High-Temperature Chemistry