Calculations of a Bluff-body-stabilized Non-premixed Flame using a Reduced Description with Tabulation of Chemistry

摘要

The reduced description of reactive flows in combination with chemistry tabulation can effectively reduce the simulation time when detailed chemical kinetics is employed in multi-dimensional Computational Fluid Dynamics (CFD). In this study, this approach is applied to simulate a bluff-body-stabilized nonpremixed flame with the eddy dissipation concept (EDC) and transported probability density function (PDF) combustion models. In the calculations, the chemical species in the GRI-1.2 mechanism are partitioned into represented species and unrepresented species. The reactive system is described in terms of a smaller number of represented species instead of the full set of chemical species in the mechanism; and the evolution equations are solved only for the represented species. The In Situ Adaptive Tabulation (ISAT) approach is employed to speed the chemistry calculation by tabulating information of the reduced system. The simulations show that a reduced description with 13 represented species agrees well with the full description that has 31 species while achieving a speed-up factor of up to 3. Compared to experimental data, the PDF model yields more accurate predictions in the composition fields of upstream locations than EDC. Moreover, in this study, an efficient initialization procedure is first demonstrated for the CFD calculations with detailed chemistry.