Amajor goal of combustion research is to develop accurate, tractable, predictive models for the phenomena occurring in combustion devices, which predominantly involve turbulent flows. With the focus on gasphase, non-premixed flames, recent progress is reviewed, and the significant remaining challenges facing models of turbulent combustion are examined. The principal challenges are posed by the ...

Thermal radiation plays a dominant role in heat transfer for most combustion systems. Accurate predictions of radiative heat transfer are essential for the correct determination of flame temperature, flame structure, and pollutant emissions in combustion simulations. In turbulent flames, transported probability density function (PDF) methods provide a reliable treatment of nonlinear processes s...

Direct numerical simulation data obtained from two turbulent, lean hydrogen–air flames propagating in a box are analyzed to explore the influence of combustion-induced thermal expansion on turbulence unburned gas. For this purpose, Helmholtz–Hodge decomposition is applied computed velocity fields. Subsequently, second-order structure functions conditioned reactants sampled divergence-free solen...

To explore the direction of inter-scale transfer scalar variance between subgrid scale (SGS) and resolved fields, direct numerical simulation data obtained earlier from two complex-chemistry lean hydrogen–air flames are analysed by applying Helmholtz–Hodge decomposition (HHD) to simulated velocity fields. Computed results show backscatter (combustion progress variable $c$ ) variance, i.e. its S...