DETAILED KINETIC MODELING OF SOOT FORMATION DURING SHOCK-TUBE PYROLYSIS OF C6H6: DIRECT COMPARISON WITH THE RESULTS OF TIME-RESOLVED LASER-INDUCED INCANDESCENCE (LII) AND CW-LASER EXTINCTION MEASUREMENTS

2004 ◽  
Vol 176 (10) ◽  
pp. 1667-1703 ◽  
Author(s):  
I. NAYDENOVA ◽  
M. NULLMEIER ◽  
J. WARNATZ ◽  
P. A. VLASOV
2015 ◽  
Vol 229 (5) ◽  
Author(s):  
Martin Leschowski ◽  
Thomas Dreier ◽  
Christof Schulz

AbstractSoot formation and oxidation in high-pressure combustion is of high practical relevance but still sparsely investigated because of its experimental complexity. In this work we present a high-pressure burner for studying sooting premixed flames at pressures up to 30 bar. An optically accessible vessel houses a burner that stabilizes a rich premixed ethylene/air flame on a porous sintered stainless-steel plate. The flame is surrounded by a non-sooting rich methane/air flame and an air coflow for reducing temperature gradients, buoyancy-induced instabilities, and heat loss of the innermost flame. Spectrally-resolved soot pyrometry was used for determining gas temperatures. These were introduced into model functions to fit the temporal signal decay curves obtained from two-color time-resolved laser-induced incandescence (TiRe-LII) measurements for extracting soot volume fractions and mean particle size as a function of height above burner and gas pressure. The derived mean particle sizes and soot concentrations were compared against thermophoretically sampled soot analyzed via transmission electron microscopy (TEM) and laser extinction measurements at 785 nm, respectively. Soot volume fractions derived from LII peak signal intensities need to be corrected for signal attenuation at the high soot concentrations present in the investigated flame. From the various heat conduction models employed in deriving mean soot particle diameters from TiRe-LII, the Fuchs model gave remarkably good agreement with TEM on sampled soot at various heights above the burner.


1985 ◽  
Vol 20 (1) ◽  
pp. 887-901 ◽  
Author(s):  
Michael Frenklach ◽  
David W. Clary ◽  
William C. Gardiner ◽  
Stephen E. Stein

2020 ◽  
Author(s):  
Subith Vasu ◽  
Ramees Rahman ◽  
Samuel Barak ◽  
Sneha Neupane ◽  
Erik Ninnemann ◽  
...  

2007 ◽  
Vol 31 (1) ◽  
pp. 575-583 ◽  
Author(s):  
G.L. Agafonov ◽  
I. Naydenova ◽  
P.A. Vlasov ◽  
J. Warnatz

Author(s):  
Christoph Hassa ◽  
Eggert Magens ◽  
Lena Voigt ◽  
Olaf Diers ◽  
Ingo Otterpohl ◽  
...  

Abstract The production and emission of soot from Kerosene JET-A1 and a blend of a different JET-A1 and 30% HEFA was investigated in a realistic multisector combustor of Rolls-Royce Deutschland. Soot concentration measurements were performed at the exit as well as in the optically accessible primary zone of the combustor. There, information of soot mass concentration is available from measurements using Laser induced incandescence and Laser extinction. At the exit of the combustor, soot particles were measured with a scanning mobility particle sizer. This resulted in particle size distributions from which soot number and mass concentrations were calculated. Within the pressurized combustor, low load points, scaled cruise and high load points were operated. For the investigated operating range which reaches to ∼50% of max pressure but preserves engine AFR, up to 75% reduction of both soot particle mass and number EI were observed for the HEFA blend in part load and 50% at the scaled high-power condition. However at the end of the primary zone, a reduction increasing with soot concentration and fuel load was recorded. This guides attention to the different oxidation characteristics for the fuels in the investigated combustor. Accordingly, larger particles were consistently measured at the exit for the HEFA blend.


2020 ◽  
Author(s):  
Subith Vasu ◽  
Ramees Rahman ◽  
Samuel Barak ◽  
Sneha Neupane ◽  
Erik Ninnemann ◽  
...  

Fuel ◽  
1995 ◽  
Vol 74 (2) ◽  
pp. 153-158 ◽  
Author(s):  
A. Alexiou ◽  
A. Williams
Keyword(s):  

1993 ◽  
Vol 321 ◽  
Author(s):  
Gregory J. Exarhos ◽  
Nancy J. Hess

AbstractIsothermal annealing of amorphous TiO2 films deposited from acidic sol-gel precursor solutions results in film densification and concomitant increase in refractive index. Subsequent heating above 300°C leads to irreversible transformation to an anatase crystalline phase. Similar phenomena occur when such amorphous films are subjected to focused cw laser irradiation. Controlled variations in laser fluence are used to density or crystallize selected regions of the film. Low fluence conditioning leads to the evolution of a subtle nanograin-size morphology, evident in AFM images, which appears to retard subsequent film crystallization when such regions are subjected to higher laser fluence. Time-resolved Raman spectroscopy has been used to characterize irradiated regions in order to follow the crystallization kinetics, assess phase homogeneity, and evaluate accompanying changes in residual film stress.


1983 ◽  
Vol 54 (1-3) ◽  
pp. 81-101 ◽  
Author(s):  
M FRENKLACH ◽  
S TAKI ◽  
M DURGAPRASAD ◽  
R MATULA
Keyword(s):  

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