Publications Details

Sensitivity analysis and verification of a 1-D surface solid combustion model for a fire CFD boundary condition

Brown, Alexander B.; Glaze, D.J.; Pierce, Flint P.

Predicting the behavior of solid fuels in response to a fire is a complex endeavor. Heterogeneity, charring, and intumescence are a few examples of the many challenges presented by some common materials. If one desires to employ a 3-dimensional computational fluid dynamics (CFD) model for fire, an accurate solid combustion model for materials at the domain boundary is often desirable. Methods for such modeling are not currently mature, and this is a current topic of research. For some practical problems, it may be acceptable to abstract the surface combustible material as a 1-dimensional reacting boundary condition. This approach has the advantage of being a relatively simple model, and may provide acceptably accurate predictions for problems of interest. Such a model has recently been implemented in Sandia's low-Mach number CFD code for reacting flows, the SIERRA/FUEGO code. Theory for the implemented model is presented. The thermal transport component of the model is verified by approximating a 1-D conduction problem with a closed form solution. The code is further demonstrated by predicting the fire behavior of a block of burning plexiglas (PMMA). The predictions are compared to the reported data from a corresponding experimental program. The predictions are also used to evaluate the sensitivity of model parameters through a sensitivity study using the same test configuration.