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Diffusion flame
About: Diffusion flame is a research topic. Over the lifetime, 9266 publications have been published within this topic receiving 233522 citations.
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TL;DR: In this article, the relative importance of Fenimore and Zeldovich mechanisms for nitric oxide formation in stretched laminar opposed-flow diffusion flames with CH 4 N 2 fuel is determined using model calculations that include detailed chemical kinetics and realistic multi-component transport effects.
113 citations
TL;DR: In this paper, an asymptotic nonlinear differential equation is derived for the evolution of a disturbed spherical flame front, and a quantitative description is presented of the formation of cellular flame structure and subsequent self-turbulization of the flame.
113 citations
TL;DR: Individual rotational lines are more clearly resolved in the DFWM spectrum than in the laser-induced fluorescence spectrum, although both are power broadened at laser intensities of 1-2 MW/cm(2) at 307 nm.
Abstract: Temperatures have been measured in a laminar premixed propane–air diffusion flame using degenerate four-wave mixing (DFWM) of the OH radical. The spectra were recorded simultaneously with laser-induced fluorescence through the (0, 0) band of the OH A2Σ–X2II transition. Individual rotational lines are more clearly resolved in the DFWM spectrum than in the laser-induced fluorescence spectrum, although both are power broadened at laser intensities of 1–2 MW/cm2 at 307 nm. Rotational temperatures have been determined from the DFWM spectra and are in close agreement with temperatures measured with coherent anti-Stokes Raman spectroscopy of nitrogen.
113 citations
TL;DR: In this paper, the spectral extinction coefficients of soot aggregates were studied in the fuel-lean (overfire) region of buoyant turbulent diffusion flames, and the specific extinction coefficients and emissivities were predicted based on Rayleigh-Debye-Gans theory for polydisperse fractal aggregates.
Abstract: The spectral extinction coefficients of soot aggregates were studied in the fuel-lean (overfire) region of buoyant turbulent diffusion flames. Extinction measurements were carried out in the wavelength region of 0.2-5.2 μm for flames fueled with acetylene, propylene, ethylene, and propane, burning in air. The present measurements were combined with earlier measurements of soot morphology and light scattering at 0.514 μm in order to evaluate the spectral soot refractive indices reported by Dalzell and Sarofim (1969), Let and Tien (1981), and Chang and Charalampopoulos (1990). The specific extinction coefficients and emissivities were predicted based on Rayleigh-Debye-Gans theory for polydisperse fractal aggregates, which has been recently found to be the best approximation to treat optical cross sections of soot aggregates. The results indicated that available refractive indices of soot do not predict the spectral trends of present measurements in the ultraviolet and infrared regions. Soot complex refractive index was inferred to be m = 1.54 + 0.48i at 0.514 μm, which is surprisingly in best agreement with the values reported by Dalzell and Sarofim (1969). Additionally, specific extinction coefficients of soot aggregates varied with wavelength as λ -0.83 from the visible to the infrared. Finally, soot refractive indices were found to be relatively independent of fuel type for the visible and infrared spectral regions over the H/C ratio range of 0.08-0.22.
113 citations
TL;DR: In this article, the numerical simulation of a turbulent non-premixed hydrogen (H 2 ) diffusion flame has been performed in a model combustor, where air 25% was staged and introduced through the two tangential inlets.
113 citations