%0 Book Section %1 favier1998numerical %A Favier, V. %A Vervisch, L. %A Hermann, M. %A Terhoeven, P. %A Binninger, Bernd %A Peters, Norbert %B Numerical Flow Simulation I %D 1998 %I Springer %K prev %P 203-221 %T Numerical Simulation of Combustion in Partially Premixed Turbulent Flows %V 66 %X To help to understand and to model lift-off in non-premixed turbulent combustion, triple flames and edge-flames are investigated in this work. In the first part of the paper the effects of unsteadiness at the edge of a diffusion flame are studied. Numbers representative of propagation and extinction properties of edge-flames are chosen, and direct numerical simulation of an edge-flame submitted to vorticity and unsteady micromixing are performed varying those key numbers. The outcome is a diagram delineating conditions for upstream and downstream propagation of an edge-flame in such environments. In addition to these direct numerical computations a modelling approach is presented to simulate partially premixed combustion in the flamelet regime which combines the flamelet models for non-premixed and premixed combustion. In the flamelet regime the calculation of the chemical processes can be separated from the flow calculation, so that the flow solver needs not resolve any chemical scales. To account for the combustion controlling mechanisms, mixing and flame propagation, transport equations for two scalars, the mixture fraction Z and the level set function G, are introduced. These quantities and the scalar dissipation rate X serve as input parameters for pre-calculated triple flame libraries which provide the chemical composition of the flow and the burning velocity s L . A hybrid tracking capturing scheme is used to solve the governing equations.

@inbook{favier1998numerical, abstract = {To help to understand and to model lift-off in non-premixed turbulent combustion, triple flames and edge-flames are investigated in this work. In the first part of the paper the effects of unsteadiness at the edge of a diffusion flame are studied. Numbers representative of propagation and extinction properties of edge-flames are chosen, and direct numerical simulation of an edge-flame submitted to vorticity and unsteady micromixing are performed varying those key numbers. The outcome is a diagram delineating conditions for upstream and downstream propagation of an edge-flame in such environments. In addition to these direct numerical computations a modelling approach is presented to simulate partially premixed combustion in the flamelet regime which combines the flamelet models for non-premixed and premixed combustion. In the flamelet regime the calculation of the chemical processes can be separated from the flow calculation, so that the flow solver needs not resolve any chemical scales. To account for the combustion controlling mechanisms, mixing and flame propagation, transport equations for two scalars, the mixture fraction Z and the level set function G, are introduced. These quantities and the scalar dissipation rate X serve as input parameters for pre-calculated triple flame libraries which provide the chemical composition of the flow and the burning velocity s L . A hybrid tracking capturing scheme is used to solve the governing equations.}, added-at = {2013-03-21T15:13:41.000+0100}, author = {Favier, V. and Vervisch, L. and Hermann, M. and Terhoeven, P. and Binninger, Bernd and Peters, Norbert}, biburl = {https://www.bibsonomy.org/bibtex/274b973cadece30a02026c65557dafcd7/itv}, booktitle = {Numerical Flow Simulation I}, interhash = {8e829d7b76061df59642ef8a617be7b8}, intrahash = {74b973cadece30a02026c65557dafcd7}, keywords = {prev}, pages = {203-221}, publisher = {Springer}, timestamp = {2018-11-22T10:32:50.000+0100}, title = {Numerical Simulation of Combustion in Partially Premixed Turbulent Flows}, volume = 66, year = 1998 }