Pressure dependent mechanism for H/O/C(1) chemistry

Document Type

Conference Proceeding

Publication Date

1-1-2007

Abstract

A pressure dependent kinetic sub-mechanism for HxOxC1 species is developed based on literature data for reactions of the hydrogen-oxygen subset and paths involving abstraction of hydrogen atoms. Pressure and temperature dependent rate constants are determined for bimolecular, chemical activation (association and addition) and unimolecular (thermal) dissociation reactions using multi-frequency QRRK analysis for k(E) and master Equation analysis for fall-off. Pressure and temperature dependent rate constants are expressed in the form of 7×3 Chebyshev polynomials over 0.01 to 100 atm and 300 to 3000K. The chemical activation systems include reactions of OH, HO2, O•, O2 with the following carbon species: CO, HC•=O, CH2=O, C• H2OH, CH3O, CH3 plus selected C2 species, with dissociation analysis for stabilized adducts. Improved rate constants are used for HO2 + CO reaction (near pressure independent) expressed as k1a= 8.45 x108xT1.21 exp(17267cal/RT) and k1b=7.14×107xT1.57 exp(17721cal/RT) cm3 mol-1 s-1 (two alternative channels leading to the same CO2+OH products via different transition states) at CBS-QB3 level calculations and QRRK/ME analysis. Chemkin model results are compared with ignition time (delay) experiments in the CO/H2/Ox system versus fuel equivalence ratio and pressure. The mechanism consists of ∼35 species and 150 reactions, with over 40 being pressure dependent.

Identifier

77955082431 (Scopus)

ISBN

[9781604238112]

Publication Title

5th US Combustion Meeting 2007

First Page

3691

Last Page

3700

Volume

6

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