Lattice-Boltzmann methods for hydrogen combustion and safety

- resp. équipe TONIC (Thermodynamique, Ondes Numérique, Interfaces, Combustion )

Abstract: Lattice-Boltzmann methods (LBM) have matured as a powerful and efficient computational fluid dynamics tool in the past two decades, in particular for aerodynamics & aeroacoustics applications. In these applications, the flow is generally governed by mass and momentum conservation, corresponding to acoustic and vorticity modes. Multi-physics extensions exist (urban flows, pollutant transport, etc), most often in cases where additional equations are weakly coupled with acoustic and vorticity modes (e.g. passive scalar transport, Boussinesq approximation). In the author's opinion, this is mainly due to the peculiar moments cascade structure - a LBM building block - being a priori incompatible with arbitrary equations of state, heat capacity, or Prandtl numbers. Several research groups have recently presented new models lifting these limitations, proving LBM to be worth the effort for flows involving strong mode couplings (in particular, the entropy mode). I will illustrate this point with a series of problems reminiscent of hydrogen combustion and safety problems, where the mode coupling is paramount: Rankine-Hugoniot relations, premixed flame instabilities, thermo-acoustic instabilities or detonations.