Said Taileb, Alejandro Millán-Merino, Song Zhao, Pierre Boivin. Lattice-Boltzmann modeling of lifted hydrogen jet flames: A new model for hazardous ignition prediction. Combustion and Flame, 2022, 245, pp.112317. ⟨10.1016/j.combustflame.2022.112317⟩. ⟨hal-03796395⟩ Plus de détails...
This numerical study deals with the hazardous ignition of a jet flame in a vitiated co-flow. A novel formulation, based on a passive scalar variable, will be presented to predict hydrogen auto-ignition events. The model, derived from the theoretical analysis of the Jacobian, correctly describes the appearance and absence of auto-ignition in complex configurations based on initial thermodynamic and mixture conditions. No chemical reaction and species equations are required to perform the simulations. Results of Lattice Boltzmann Methods (LBM) simulations of a 3D H 2 /N 2 Cabra flame will be presented using a detailed H 2-Air mechanism. Validation against experimental and numerical results will be provided for the lift-off (distance to auto-ignition). The passive scalar predictions are successfully compared with the reactive simulations. The results show a potential extension of this model to an extensive spectrum of hydrogen safety and large-scale turbulent combustion applications.
Said Taileb, Alejandro Millán-Merino, Song Zhao, Pierre Boivin. Lattice-Boltzmann modeling of lifted hydrogen jet flames: A new model for hazardous ignition prediction. Combustion and Flame, 2022, 245, pp.112317. ⟨10.1016/j.combustflame.2022.112317⟩. ⟨hal-03796395⟩
Alejandro Millán-Merino, Said Taileb, Pierre Boivin. A new method for systematic 1-step chemistry reduction applied to hydrocarbon combustion. Proceedings of the Combustion Institute, 2022, ⟨10.1016/j.proci.2022.08.052⟩. ⟨hal-03825847⟩ Plus de détails...
We propose a new single-step mechanism for the combustion of arbitrary hydrocarbons and alcohols. Unlike most single-step models, no tabulation is required, as the method builds upon a new analytical description of the thermochemical equilibrium of fuel-oxidizer mixtures including dihydrogen and carbon monoxide-two species usually discarded in one-step descriptions-yielding correct adiabatic temperature. The single-step chemistry includes varying stoichiometric coefficients, ensuring a convergence towards thermochemical equilibrium regardless of the local state. The reaction rate is then carefully adjusted to reproduce accurately premixed flames. To tackle ignition simultaneously, an additional passive scalar advection-diffusion-reaction equation is introduced, with a rate fitted on ignition delays. The scalar then serves as an efficiency to modify the single-step reaction rate in autoignition configurations. The obtained scheme is then validated for a wide range of equivalence ratios on homogeneous reactors, premixed flames, a triple flame, and a counterflow diffusion flame. The new analytical thermochemical equilibrium formulation may also serve in speeding up infinitely fast chemistry calculations.
Alejandro Millán-Merino, Said Taileb, Pierre Boivin. A new method for systematic 1-step chemistry reduction applied to hydrocarbon combustion. Proceedings of the Combustion Institute, 2022, ⟨10.1016/j.proci.2022.08.052⟩. ⟨hal-03825847⟩
