Heat and Mass Transfer in Turbulent Combustion

This review outlines the impact on our understanding of turbulent combustion being made by advanced laser measurement techniques and direct numerical simulation (DNS). In turbulent premixed flames the direction of the turbulent scalar flux can be up or down the mean gradient of the scalar. DNS and particle imaging velocimetry (PIV) show that this is related to the flamefront structure. Temperature gradients and radical concentrations are also affected, but apparently from a different cause. In nonpremixed systems DNS has helped to improve understanding of the validity and limitations of advanced models for combustion-turbulence interactions, and has also led to a new model for differential diffusion effects in mixing and combustion. Laser measurements have been made of the conditional dissipation of the mixture fraction.