Flamelet generated manifold modeling for biomass combustion

A major challenge in combustion simulations is the inclusion of finite-rate chemistry effects. Finite-rate chemistry effects of biomass (red oak) combustion are included through the creation of flamelet generated manifolds (FGM). Wood pyrolysis products are determined via a multiphase chemical equilibrium solver based on the STANJAN solver at constant pressure and specified pyrolysis temperature. Detailed reaction chemistry of wood pyrolysis products with air are tabulated using a reduced mechanism by differing the flame strain rates. Flamelet results are cataloged as a function of mixture fraction and a progress variable (C), defined as a weighted sum of product species using a downhill simplex method to minimize the defined cost function. The utility of the FGM is assessed by conducting transient one-dimensional calculations of flame progression for several mass blowing rates as a preliminary step with the intent of extending the theory to multi-dimensional flame spread problems. Results are compared using FGM and full finite-rate chemistry. Overall good agreement, with a maximum of about 2% error observed between peak temperatures is observed for the limiting case of zero mass blowing; while errors in mass blowing cases reach a maximum of ∼9% for major species and approximately 20% for temperature profiles.