Consistent lattice Boltzmann model for reactive mixtures

TL;DR

This paper introduces a thermodynamically consistent lattice Boltzmann model for reactive mixtures, capable of simulating complex combustion processes with validated accuracy against direct numerical simulations.

Contribution

The paper presents a novel reactive lattice Boltzmann model incorporating reaction mechanisms, extended equilibrium for compressible flows, and thermodynamic consistency for reactive mixtures.

Findings

Accurate simulation of hydrogen/air combustion in microchannels.

Validation against direct numerical simulations shows excellent agreement.

Model effectively captures various burning regimes in reactive flows.

Abstract

A new lattice Boltzmann model (LBM) for chemically reactive mixtures is presented. The approach capitalizes on the recently introduced thermodynamically consistent LBM for multicomponent mixtures of ideal gases. Similar to the non-reactive case, the present LBM features Stefan--Maxwell diffusion of chemical species and a fully on-lattice mean-field realization of the momentum and energy of the flow. Besides introducing the reaction mechanism into the kinetic equations for the species, the proposed LBM also features a new realization of the compressible flow by using a concept of extended equilibrium on a standard lattice in three dimensions. The full thermodynamic consistency of the original non-reactive multicomponent LBM enables to extend the temperature dynamics to the reactive mixtures by merely including the enthalpy of formation in addition to the previously considered sensible energy. Furthermore, we describe in detail the boundary conditions to be used for reactive flows of practical interest. The model is validated against a direct numerical simulation of various burning regimes of a hydrogen/air mixture in a microchannel, in two and three dimensions. Excellent comparison in these demanding benchmarks indicates that the proposed LBM can be a valuable and universal model for complex reactive flows.