Level-set flamelet library approach for premixed turbulent combustion

Modeling of a lean premixed propane/air turbulent flame stabilized by a blu ff body is presented. The laminar flamelet library approach, which has been successfully used for modeling of nonpremixed turbulent flames, is extende d and applied to premixed combustion. In this approach the mean flame locat ion and mean flame thickness are modeled by a level-set G-equation and a G- variance equation, along with empirical expressions. The detailed species c oncentrations, temperature and density are calculated using a presumed prob ability density function (PDF) together with a laminar flamelet library, wh ich is generated using a detailed chemical kinetic mechanism. The sensitivi ty of the results to the model components is investigated. It is shown that the temperature and major species concentrations are not very sensitive to the model components such as the turbulent flame speed and the shape of th e presumed PDF. Species which only exist in the inner layer of the laminar flamelet an found to be more sensitive to the model components. Comparisons of calculations with experimental data indicate that the flamelet library approach is able to predict the major properties of the mean turbulent flam e. In particular the method exhibits potential in simulation of minor pollu tant species such as NO,, with fairly detailed chemistry at a low cost. (C) 2000 Elsevier Science Inc. All rights reserved.