Laser Diagnostics for the Model Development in Turbulent Premixed Flames

摘要

The interaction of turbulent flow and chemical processes is complex. Due to the strong turbulent fluctuations on very small scales, a direct insight into the processes has not been possible for long time. New laser diagnostics with sufficient spatial and temporal resolution allow now the answer to long discussed questions, for instance concerning the contradictory ideas of thin or thickened flame fronts in turbulent premixed combustion. More and more also numerical models allow the combined calculation of the local processes describing turbulent flow and combustion reaction. However, often unknown terms coming from the averaging procedure of the turbulence models need to have closures. Advanced application of the planar PIV measurement technique allowed the velocity field evaluation conditioned to the either unburnt or burnt gas state in turbulent premixed flames. Herewith, the direct evaluation of unclosed model terms has been possible for both RANS models as well as for models for the large-eddy simulation method. The mutual interaction of advanced laser diagnostics and numerical models is seen as one of the milestones for the development of advanced technical combustion.