Large eddy simulation of a model gas turbine combustor

Large eddy simulation (LES) has been used to predict temperature and species concentrations in a model can-type gas turbine combustor operating in a non-premixed combustion regime. The subgrid scale stresses have been modelled adopting the standard Smagorinsky-Lilly model, whilst combustion has been accounted for using a conserved scalar approach. The dependence of the thermodynamical status of the mixture on the conserved scalar has been described invoking a flamelet assumption, and the shape of the scalar probability density function (pdf) assigned to be a beta function. The subgrid scalar variance, needed to parameterise the scalar pdf, has been modelled according to local equilibrium arguments. The complex flow pattern developing from the interaction of a strongly swirling flow in the primary zone with the impinging primary jets has been captured by the present simulations in great detail. In particular, it has been observed that an accurate description of the inlet section of the combustor plays a fundamental role in the prediction of the fuel placement and, hence, of the temperature distribution in the primary region. (C) 2004 The Combustion Institute. Published by Elsevier Inc. All rights reserved.