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Mixing and Radiation Properties of Buoyant Luminous Flame Environments.


pdf icon Mixing and Radiation Properties of Buoyant Luminous Flame Environments. (4134 K)
Dai, Z.; Krishnan, S. K.; Sangras, R.; Wu, J. S.; Faeth, G. M.

NIST GCR 96-691; GDL/GMF-95-02; 90 p. June 1996.

Sponsor:

National Institute of Standards and Technology, Gaithersburg, MD

Available from:

National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161.
Telephone: 1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900; Rush Service (Telephone Orders Only) 800-553-6847;
Website: http://www.ntis.gov
Order number: PB96-202254

Keywords:

diffusion flames; fire research; optical properties; soot; turbulent flames

Abstract:

An investigation of the radiation and mixing properties of buoyant turbulent diffusion flames is described. The study was divided into two phases: (1) the optical and radiative properties of soot, which must be understood in order to develop non-intrusive methods for measuring soot properties and to estimate the continuum radiation properties of soot in flame environments, and (2) the structure and mixing properties of buoyant turbulent plumes, which must be understood in order to resolve effects of turbulence/radiation interactions and to benchmark computationally tractable models of buoyant turbulent flows. Consideration of the optical and radiative properties of soot involved evaluation of the Rayleigh-Debye-Gans (RDG) scattering approximation for soot aggregates and the use of this theory to measure the refractive indexes in the visible region (350-800 nm). In addition, dimensionless extinction coefficients and the soot fractal dimensions were measured. The structure and mixing properties of buoyant turbulent plumes were investigated by examination of the effects of coflow on earlier measurements and by evaluating various modeling approximations, with an emphasis on self-preserving round buoyant turbulent plumes.