Fire dynamics simulations of a one-meter diameter methane fire

A one-meter diameter-methane fire was simulated to validate a fire dynamics simulation code for large-scale fires. A uniform grid size of 2.5 cm in the entire computational domain is used. Therefore, only large-scale motions of the fire are resolved. The subgrid-scale heat release is modeled using a mixture-fraction-based combustion model. The radiative heat loss is computed using two methods: a fixed radiative fraction method and a finite volume method. The computed puffing cycle frequency is affected very weakly by the radiation heat loss. The vertical velocity magnitudes without considering radiation heat loss are about 15% higher, particularly at locations farther away from the burner exit. Good agreement between the predictions and the recent data from Tieszen and co-workers at Sandia National Laboratory confirms the feasibility of fire dynamics simulations of relatively large fires.