ID#: 164
Abstract Title: Time Resolved Flow Characteristics of Confined Turbulent Gaseous Explosions
Session Title: Gas Explosions
Session Date: 7/30/01
Session Start Time: 11:20 AM
Contributing Author: Lindstedt, P.R.
Organization: Imperial College
Country: U.K.
Authors: R.P. Lindstedt, H.A. McCann
Short Abstract: The transition of a turbulent flame to a gaseous explosion in a confined pre-existing turbulent flow field is of direct scientific and practical interest. Related topics include the intentional transition to detonation in pulsed detonation engines and industrial hazard assessment. Experimental data sets suitable for the developments of predictive techniques are required in order to advance the basic understanding of such flows. The present paper thus outlines an experimental study into the interactions between baffle accelerated premixed turbulent flames and their self-generated flow in a long closed flame tube. In particular, the effects of a pre-existing velocity field at the ignition point located upstream of the baffle are examined. Flow characteristics, including time-resolved mean and rms profiles in a two-dimensional plane, have been obtained using laser Doppler anemometry for a stoichiometric methane-air flame. Instantaneous spark schlieren photographs have been obtained around the baffle to elucidate the flame behaviour and qualitatively describe the burning process. The present configuration yields over-pressures of around 200 kPa and peak mean velocities around 150 m/s – both significantly higher than those reported by Lindstedt & Sakthitharan (1998) for initially quiescent mixtures.