Flamelet Modeling of Soot Formation in Laminar Ethyne/Air-Diffusion Flames

摘要

Formation, surface growth, and oxidation of soot in an axisymmetric laminar diffusion flame have been calculated using a detailed chemical model for soot formation and oxidation. The laminar flamelet concept has been employed to couple chemical reactions in the gas phase with the flow field. The flow field of the flame is calculated by solving the Navier-Stokes equations in axisymmetric formulation using the SIMPLER algorithm for pressure correction. In addition to the momentum conservation equations, a conservation equation for the mixture fractio and a trasnsport equation for hte soot volume fraction are solved in the CFD code. The requried source terms for the transport equation for the soot volume fraction are calculated in the mixture fraction/scalar dissipation rate space for laminar flamelets and tabulated in a library. Surface growth and oxidatio rates are weighted with the locally calculated soot volume fractins, whereas the source term for particle inception is taken directly from the flamelet calculations.