ID#: 113
Abstract Title: Burning Velocity Measurements in Aluminum-Air Suspensions Using Stabilized Dust Flames
Session Title: Dust and Metal Containing Flames
Session Date: 7/30/01
Session Start Time: 2:00 PM
Contributing Author: Goroshin, S.V.
Organization: McGill University
Country: Canada
Authors: Samuel Goroshin, Massimiliano Kolbe, John Lee
Short Abstract: Laminar burning velocity is an important combustion characteristic of the premixed combustible mixture. The majority of experimental data on burning velocities in gaseous mixtures was obtained with the help of the Bunsen conical flame. Hans Cassel was the first to demonstrate that suspensions of micron-size solid fuel particles in a gaseous oxidizer can also form self-sustained Bunsen flames. Dust flames in comparison to gas flames are thicker, may be influenced by radiation heat transfer in the flame front, respond differently to heat losses, and are fundamentally influenced by the particular flow configuration due to the particles inertia. With greater sensitivity to a specific experimental situation the introduction of the very concept of the fundamental flame speed may be problematic for dust combustion. The present work investigates to what degree burning velocities derived from Bunsen cone depend on experimental conditions (i.e. flow rate and nozzle diameter). Modified experimental apparatus permits stabilization of the aluminum Bunsen-type dust flames on conical nozzles with accurate measurement of the dust concentration and dust flow rate. Experimental results show that burning velocities in aluminum-air suspensions considerably increase with the increase of flow rate and decrease with increase in nozzle diameter. Theoretical estimations show that radiation heat transfer and flame curvature effects are small and can not alone explain the observed experimental trends. Thus other effects such as heat losses and (or) peculiarities of the two-phase flow dynamics might be responsible for the dependence of burning velocity on the flame scales observed in the present work.