Effects of updated transport properties of singlet oxygen species on steady laminar flame simulations

摘要

A current problem is distinguishing the relative contributions of chemical kinetic and transport effects to the enhancement of plasma-assisted combustion. As numerical investigations in plasma-assisted combustion move to simulations in one or more dimensions, the transport properties of excited-state species thought to contribute to the combustion enhancement will need to be determined to accurately model these systems and discern their chemical kinetic contribution to the enhancement. We provide estimates of the intermolecular interaction energies of singlet oxygen (O_2(a~1Δ_g) and O_2(b~1Σ_g~+)) using ab initio quantum chemistry methods, and find that the transport properties derived from these interaction energies are substantially different from those of the corresponding ground state. One-dimensional simulations of both premixed and non-premixed steady low-pressure methane flames seeded with 2.5% O_2(a~1Δ_g) in the oxidizer were performed. Results indicate that updating the transport properties of the singlet oxygen species has a very small effect on flame speed and structure, but that this effect is largest in premixed flame simulations due to reactions of O_2(a~1Δ_g) with H atoms.