Large Eddy Simulations of a Small-Scale Flameless Combustor by Means of Diluted Homogeneous Reactors

Autor: Jean-Baptiste Michel, Olivier Colin, Carlo Locci
Rok vydání: 2014
Předmět:
Zdroj: Flow, Turbulence and Combustion. 93:305-347
ISSN: 1573-1987
1386-6184
DOI: 10.1007/s10494-014-9548-2
Popis: A new model for Flameless Combustion (FC) based on the tabulation of diluted homogeneous reactors (DHR) is presented. This model is developed within the Large Eddy Simulations (LES) approach because LES has a good potential for correctly predicting the ternary mixing of FC. In DHR, a ternary mixture of fuel, air and burnt gases at equilibrium is considered as an initial condition for the reactor calculations. The auto-ignition of this mixture is then tabulated as a function of the input parameters which are mixture fraction, fresh gases temperature, dilution fraction, progress variable and enthalpy loss. The enthalpy loss is introduced by decreasing the temperature of the diluting burnt gases. The DHR model is first evaluated over the partially premixed Sandia Flame D. Correct results are obtained for this flame, although CO is overestimated by the model. This discrepancy is attributed to the usage of homogeneous reactors which impedes to account for the influence of scalar dissipation. Secondly, the flameless configuration of Verissimo et al., characterized by a strong enthalpy loss due to wall heat losses, is used to assess the performance of the model. Combustion results are found in correct agreement for temperature and major species. The largest discrepancies are found for CO again, although the axial shape for this species is correctly predicted.
Databáze: OpenAIRE
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