ID#: 43
Abstract Title: Propagation and Extinction of Unsteady Spherical Spray Flame Fronts
Session Title: Gasless and Dust Containing Flames
Session Date: 7/30/01
Session Start Time: 3:40 PM
Contributing Author: Greenberg, J.
Organization: Technion - Israel Institute of Technology
Country: Israel
Authors: J.B. Greenberg
Short Abstract: The question of the ignition of a mist of fuel droplets is of prime importance in a variety of aeronautical contexts. There is sparse experimental evidence available in the literature and theoretical efforts have generally resulted in rule of thumb formulae. In the current work the related problem of a spherical flame front propagating through a fuel rich mixture of fuel droplets and air is examined theoretically for the first time. The SVF (slowly varying flame) framework is adopted for the analysis. Upon attaining their boiling temperature the droplets are assumed to vaporize in a vaporization front, downstream of the propagating flame front, whose location as a function of time is determined as part of the solution. An evolution equation for the flame front is derived. It is shown that the droplets supply a heat loss term in this equation involving the droplet loading and the latent heat of vaporization of the liquid fuel. Calculated results demonstrate the way in which increasing the droplet loading beyond some critical value actually causes the flame front to extinguish.