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Large eddy simulations with three-dimensional finite-volume ConditionalMoment Closure (CMC) model are performed for a hydrogen / nitrogen lifted flamewith detailed chemical meachanism. The emphasis is laid on the influences ofmesh resolution and convection scheme of finite-volume CMC model on predictionsof reactive scalar distribution and unsteady flame dynamics. The results showthat the lift-off height is underestimated and the reactive scalars (e.g.temperature, H2 and OH) are over-predicted with coarser CMC mesh. It is alsofound that further refinement of the CMC mesh would not considerably improvethe results. The time sequences of the most reactive and stoichiometric OH massfractions indicate that finer CMC mesh can capture more unsteady details thancoarser CMC mesh. Moreover, the coarse CMC mesh has lower conditional scalardissipation rate, which would promote the ealier auto-ignition of the flamebase. Besides, the effects of the convection schemes in the CMC equations onthe lifted flame characteristics are also investigated. It is shown thatdifferent convection schemes lead to limited differences on the time-averagedtemperature, mixture fraction and species mass fractions. Moreover, the RMSvalues of H2 and OH mass fractions show larger deviation from the measurementswith hybrid upwind and central differencing scheme, especially around the flamebase. Furthermore, the distributions of the numerical flux on the CMC facesalso show obvious distinction between the upwind scheme and the blendingscheme. The budget analysis of the individual CMC terms shows that a sequenceof CMC faces has comparable contributions with upwind scheme. However, with thehybrid schemes, the instantaneous flux is dominantly from limited CMC faces.The reactivity of a CMC cell is more easily to be affected by its neighborswhen the upwind scheme is used.

LES and finite-volume CMC modelling of a turbulent lifted H2/N2 flame: effects of CMC mesh resolution and numerical scheme