Turbulent premixed combustion: A flamelet formulation and spectral analysis in theory and IC-engine experiments

Abstract

A flamelet formulation for premixed combustion has been derived based on a scalar field equation describing the instantaneous flame front location in the turbulent flow field. This partial differential equation is equivalent to the local kinematic balance between fluid flow velocity, burning velocity and flame propagation velocity. If the burning velocity depends locally on flame stretch and flame front curvature, an additional length scale, the Markstein length is introduced into the problem. A spectral closure of the problem has been performed on the basis of a two-point correlation. The transformation of the scalar field equation into wavenumber-space leads to the definition to a spectrum function for the fluctuations of the turbulent flame front. The cut-off of the inertial subrange occurs at the Gibson scale.