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Determination of the Rate Coefficients of the SO2 plus O plus M yields SO3 plus M ReactionRate coefficients of the title reaction R(sub 31) (SO2 +O+M yields SO3 +M) and R(sub 56) (SO2 + HO2 yields SO3 +OH), important in the conversion of S(IV) to S(VI),were obtained at T =970-1150 K and rho (sub ave) = 16.2 micro mol/cubic cm behind reflected shock waves by a perturbation method. Shock-heated H2/ O2/Ar mixtures were perturbed by adding small amounts of SO2 (1%, 2%, and 3%) and the OH temporal profiles were then measured using laser absorption spectroscopy. Reaction rate coefficients were elucidated by matching the characteristic reaction times acquired from the individual experimental absorption profiles via simultaneous optimization of k(sub 31) and k(sub 56) values in the reaction modeling (for satisfactory matches to the observed characteristic times, it was necessary to take into account R(sub 56)). In the experimental conditions of this study, R(sub 31) is in the low-pressure limit. The rate coefficient expressions fitted using the combined data of this study and the previous experimental results are k(sub 31,0)/[Ar] = 2.9 10(exp 35) T(exp ?6.0) exp(?4780 K/T ) + 6.1 10(exp 24) T(exp ?3.0) exp(?1980 K/T ) cm(sup 6) mol(exp ?2)/ s at T = 300-2500 K; k(sub 56) = 1.36 10(exp 11) exp(?3420 K/T ) cm(exp 3)/mol/s at T = 970-1150 K. Computer simulations of typical aircraft engine environments, using the reaction mechanism with the above k(sub 31,0) and k(sub 56) expressions, gave the maximum S(IV) to S(VI) conversion yield of ca. 3.5% and 2.5% for the constant density and constant pressure flow condition, respectively. Moreover, maximum conversions occur at rather higher temperatures (?1200 K) than that where the maximum k(sub 31,0) value is located (approximately 800 K). This is because the conversion yield is dependent upon not only the k(sup 31,0) and k(sup 56) values (production flux) but also the availability of H, O, and HO2 in the system (consumption flux).
Document ID
20110010915
Acquisition Source
Glenn Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
doi:10.1002/kin.20472
Authors
Hwang, S. M. (Toledo Univ. Toledo, OH, United States)
Cooke, J. A. (Toledo Univ. Toledo, OH, United States)
De Witt, K. J. (Toledo Univ. Toledo, OH, United States)
Rabinowitz, M. J. (NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 25, 2013
Publication Date
March 1, 2010
Publication Information
Publication: International Journal of Chemical Kinetics
Volume: 42
Issue: 3
Subject Category
Inorganic, Organic And Physical Chemistry
Report/Patent Number
E-17702
Funding Number(s)
CONTRACT_GRANT: NRA-01-GRC02 Phase2
Distribution Limits
Public
Copyright
Public Use Permitted.

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