Experimental and numerical analysis of a lean premixed stratified burner using 1D Raman/Rayleigh scattering and large eddy simulation

A joint experimental and numerical approach is conducted to investigate a turbulent lean premixed stratified flame (flame TSF-A of the Darmstadt stratified burner). First, the distribution of the temperature and main species is obtained experimentally by 1D Raman/Rayleigh scattering. These measurements are used to provide insight into the physics of stratified combustion and to serve as validation data for numerical models. As a second step Large Eddy Simulations (LES) are carried out using tabulated chemistry combined with a thickened flame approach. The chemistry table uses the progress variable and additionally the mixture fraction as a second controlling variable to account for the variation in equivalence ratio. To test the applicability of the model, the influence of artificial thickening on the simulation of stratified flames is investigated by means of a one-dimensional test case. Furthermore, two different grids are used in the three-dimensional simulations to assess the modeling impact. The data obtained from the measurements and simulations are presented and compared along radial profiles at several axial positions. Further information about the interaction of the reaction zone with the mixing layer has been extracted from the LES which is currently not accessible by experiments.