Peak gas velocities and flame heights of buoyancy-controlled turbulent diffusion flames

It is found that a parameter ξ, which is closely related to the local Froude number in a turbulent plume over an axisymmetric fire source, can be considered to be a universal constant throughout the nonreacting plume and, often, even into the intermittent flame region. This constancy implies that maximum gas velocities associated with buoyancy-controlled turbulent diffusion flames can be readily predicted; the consequences are examined in a simple model for correlating flame-height observations. The model leads to a correlating parameter for non-dimensional flame height which, in practice, differs from Steward's “combustion number” primarily by the appearance of the fraction of total heat release carried as convective heat into the plume.