Technical Report 160, c4e-Preprint Series, Cambridge
Skeletal chemical mechanism of high-temperature TEOS oxidation in hydrogen-oxygen environment.
Reference: Technical Report 160, c4e-Preprint Series, Cambridge, 2015
- A skeletal mechanism describing TEOS oxidation in flames is proposed.
- A three-stage reduction is used to eliminate unimportant species and reactions.
- Rate parameters for the main TEOS decomposition pathways are refined using transition state theory.
- Energetics of the key reaction channels is improved using CBS-Q method.
This paper improves the tetraethoxysilane (TEOS) oxidation mechanism proposed
by Nurkowski et al. (Proc. Comb. Inst., 35:2291-2298, 2015) by refining the rate parameters
of the key reaction channels in the mechanism. A skeletal version of the mechanism
is proposed for hydrogen-oxygen environment. The rates of ethylene-loss from
(tetra-, tri-, di- and dimethyldi-) ethoxysilane are computed using transition state theory.
The energetics of the main pathways are refined by performing detailed ab initio
calculations using the CBS-Q technique. An analysis of ethanol formation via silicates
is also performed resulting in the addition of 27 new silica species to the model. Thermodynamic
properties for these species are calculated via the balanced reactions method.
Reasonably good agreement between the improved model and available experimental data
is observed. The subsequent elimination of unimportant species and reactions is achieved
via a three-stage reduction procedure. The first and second stages involve the Direct Relation
Graph with Error Propagation (DRGEP) method, whereas the third stage analyses rate
of progress of each reaction. The investigated conditions are taken from the experimental
studies of TEOS oxidation in oxygen-hydrogen flames. The final skeletal mechanism
comprises 70 species and 457 reactions and retains good reproduction of the key model
properties across the chosen operating conditions as compared to the full mechanism.
Material from this preprint has been published in Combustion and Flame.
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