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Title: Sooting tendencies of diesel fuels, jet fuels, and their surrogates in diffusion flames

Authors:
; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1415245
Grant/Contract Number:
1258654; de-ac04-94al85000
Resource Type:
Journal Article: Publisher's Accepted Manuscript
Journal Name:
Fuel
Additional Journal Information:
Journal Volume: 197; Journal Issue: C; Related Information: CHORUS Timestamp: 2017-12-30 04:43:38; Journal ID: ISSN 0016-2361
Publisher:
Elsevier
Country of Publication:
United Kingdom
Language:
English

Citation Formats

Das, Dhrubajyoti D., McEnally, Charles S., Kwan, Thomas A., Zimmerman, Julie B., Cannella, William J., Mueller, Charles J., and Pfefferle, Lisa D. Sooting tendencies of diesel fuels, jet fuels, and their surrogates in diffusion flames. United Kingdom: N. p., 2017. Web. doi:10.1016/j.fuel.2017.01.099.
Das, Dhrubajyoti D., McEnally, Charles S., Kwan, Thomas A., Zimmerman, Julie B., Cannella, William J., Mueller, Charles J., & Pfefferle, Lisa D. Sooting tendencies of diesel fuels, jet fuels, and their surrogates in diffusion flames. United Kingdom. doi:10.1016/j.fuel.2017.01.099.
Das, Dhrubajyoti D., McEnally, Charles S., Kwan, Thomas A., Zimmerman, Julie B., Cannella, William J., Mueller, Charles J., and Pfefferle, Lisa D. 2017. "Sooting tendencies of diesel fuels, jet fuels, and their surrogates in diffusion flames". United Kingdom. doi:10.1016/j.fuel.2017.01.099.
@article{osti_1415245,
title = {Sooting tendencies of diesel fuels, jet fuels, and their surrogates in diffusion flames},
author = {Das, Dhrubajyoti D. and McEnally, Charles S. and Kwan, Thomas A. and Zimmerman, Julie B. and Cannella, William J. and Mueller, Charles J. and Pfefferle, Lisa D.},
abstractNote = {},
doi = {10.1016/j.fuel.2017.01.099},
journal = {Fuel},
number = C,
volume = 197,
place = {United Kingdom},
year = 2017,
month = 6
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on February 27, 2018
Publisher's Accepted Manuscript

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  • The structure of an ethylene counterflow diffusion flame doped with 2000 ppm on a molar basis of either jet fuel or two jet fuel surrogates is studied under incipient sooting conditions. The doped flames have identical stoichiometric mixture fractions (z{sub f} = 0.18) and strain rates (a = 92 s{sup -1}), resulting in a well-defined and fixed temperature/time history for all of the flames. Gas samples are extracted from the flame with quartz microprobes for subsequent GC/MS analysis. Profiles of critical fuel decomposition products and soot precursors, such as benzene and toluene, are compared. The data for C7-C12 alkanes aremore » consistent with typical decomposition of large alkanes with both surrogates showing good qualitative agreement with jet fuel in their pyrolysis trends. Olefins are formed as the fuel alkanes decompose, with agreement between the surrogates and jet fuel that improves for small alkenes, probably because of an increase in kinetic pathways which makes the specifics of the alkane structure less important. Good agreement between jet fuel and the surrogates is found with respect to critical soot precursors such as benzene and toluene. Although the six-component Utah/Yale surrogate performs better than the Aachen surrogate, the latter performs adequately and retains the advantage of simplicity, since it consists of only two components. The acetylene profiles present a unique multimodal behavior that can be attributed to acetylene's participation in early stages of formation of soot precursors, such as benzene and other large pyrolysis products, as well as in the surface growth of soot particles. (author)« less
  • Currently, modeling the combustion of aviation fuels, such as JP-8 and JetA, is not feasible due to the complexity and compositional variation of these practical fuels. Surrogate fuel mixtures, composed of a few pure hydrocarbon compounds, are a key step toward modeling the combustion of practical aviation fuels. For the surrogate to simulate the practical fuel, the composition must be designed to reproduce certain pre-designated chemical parameters such as sooting tendency, H/C ratio, autoignition, as well as physical parameters such as boiling range and density. In this study, we focused only on the sooting characteristics based on the Threshold Sootmore » Index (TSI). New measurements of TSI values derived from the smoke point along with other sooting tendency data from the literature have been combined to develop a set of recommended TSI values for pure compounds used to make surrogate mixtures. When formulating the surrogate fuel mixtures, the TSI values of the components are used to predict the TSI of the mixture. To verify the empirical mixture rule for TSI, the TSI values of several binary mixtures of candidate surrogate components were measured. Binary mixtures were also used to derive a TSI for iso-cetane, which had not previously been measured, and to verify the TSI for 1-methylnaphthalene, which had a low smoke point and large relative uncertainty as a pure compound. Lastly, surrogate mixtures containing three components were tested to see how well the measured TSI values matched the predicted values, and to demonstrate that a target value for TSI can be maintained using various components, while also holding the H/C ratio constant. (author)« less
  • One of the accepted measures of sooting tendencies of hydrocarbon fuels in premixed flames is the threshold fuel/oxidizer ratio, /var phi/, which assumes combustion to CO/sub 2/ and H/sub 2/O. In this analysis it has been found that this sooting can be accurately predicted by using the group additivity approach based on the nature of the individual carbon atoms that exist in the fuel molecule. The only parameters needed for this prediction are the numbers of sp/sup 3/, sp/sup 2/, sp, aromatic and benzylic carbons along with the total number of hydrogen atoms in the molecule. This approach has beenmore » used for the calculation of the sooting tendencies of 73 fuels whose measured /var phi/ has been reported in the literature. Even though the structure of these fuels varied widely and included alkanes, olefins, alkynes and aromatics, the calculated values were always very close to the measured ones. In fact, in 88% of the cases the predicted values lie within 5% of the measured ones, whereas the deviation in the rest never exceeds 10%.« less
  • Soot zone structures of counterflow and co-flow diffusion flames have been studied experimentally using the soot extinction-scattering, polycyclic aromatic hydrocarbon fluorescence, and laser Doppler velocimetry measurements. The counterflow flame has been numerically modelled with detailed chemistry. Results show that two different categories of sooting flame structures can be classified depending on the relative transport of soot particles to flames. These are the soot formation-oxidation flame and the soot formation flame. The soot formation-oxidation flame characteristics are observed in counterflow flames when located on the fuel side and in normal co-flow flames. In this case, soot particles are transported toward themore » high temperature region or the flame and experience soot inception, coagulation-growth, and oxidation. The soot formation flame characteristics are observed in counterflow flames when located on the oxidizer side and in inverse co-flow flames. In this case, soot particles are transported away from the flame without experiencing oxidation and finally leak through the stagnation plane in counterflow flames or leave the flame in inverse co-flow flames. Sooting limit measurements in both flames also substantiate the two different sooting flame structures and their characteristics.« less