Simulation of an ethylene wall fire using the spatially-evolving one-dimensional turbulence model

The mechanism of flame propagation in fuel beds of wildland fires is important to understand in order to quantify fire spread rates. Fires spread by radiative and convective heating and often require direct flame contact to achieve ignition. The flame interface in an advancing fire is unsteady and turbulent, making study of intermittent flames in complex fuels difficult. A vertical wall fire, in which ethylene fuel is slowly fed through a porous ceramic, is modeled to investigate unsteady turbulent flames in a controlled environment. Simulations of this configuration are performed using a spatial formulation of the one-dimensional turbulence (ODT) model which is able to resolve individual flames (a key property of this model) and provide realistic turbulent statistics. ODT solves diffusion-reaction equations along a notional line of sight perpendicular to the wall that is advanced vertically. Turbulent advection is modeled through stochastic domain mapping processes. Simulations include radiation and soot effects and are compared to experimental temperature data taken over a range of fuel flow rates. Flame structure, velocities, soot, and temperature statistics are reported. The ODT model is shown to capture the evolution of the flame and describe the intermittent properties at the flame edge.