J. Badra, A.R. Masri, A. Farooq
Fuel, 113, pp. 467-480, (2013)
Catalytic combustion, Homogeneous and heterogeneous reactions, Sensitivity analysis
This paper presents a sensitivity study for the oxidation of methane (CH4) over platinum (Pt). Some dominant reactions in the CH4–Pt
surface chemistry were identified and the rates of these reactions were
subsequently modified to enhance the calculations. Initially, a range
of CH4–Pt surface mechanisms available in the literature are
used, along with the relevant detailed gaseous chemistry to compute the
structure of premixed compressed natural gas (CNG)/air flames co-flowing
around a flat, vertical, unconfined, rectangular, and platinum plate.
Comparison with existing measurements of surface temperature and species
concentrations revealed significant discrepancies for all mechanisms.
Sensitivity analysis has identified nine key reactions which dominate
the heterogeneous chemistry of methane over platinum. The rates of these
reactions were modified over a reasonable range and in different
combinations leading to an “optimal” mechanism for methane/air surface
chemistry on platinum. The new mechanism is then used with the same flow
geometry for different cases varying the temperature of the incoming
mixture (Tjet), its equivalence ratio (Ф)
and the Reynolds number (Re). Results from the modified surface
mechanism demonstrate reasonably good agreement with the experimental
data for a wide range of operating conditions.