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Published January 1987 | public
Journal Article

Laser Soot-Scattering Imaging of a Large Buoyant Diffusion Flame

Abstract

A novel diagnostic technique, which makes use of laser light scattered by soot particles, was used in an effort to identify the flame sheets within a natural gas diffusion flame. Soot particles, inherently created and consumed in the flame, were used as the scattering medium, which obviated the need for externally supplied seed material. Since no foreign material was added to the flame, the current technique can be considered truly nonintrusive. The soot distribution within a large buoyant natural gas diffusion flame is argued to be a reasonable marker of the flame sheets. Measurements made in 47.4-190 kW natural gas flames stabilized on a 0.5 m diameter burner show that the flame sheets are highly wrinkled and convoluted surfaces. The flame sheets are distributed fairly uniformly within the instantaneous volume of the flame, based on images of the associated soot, and the instantaneous flame volume is devoid of soot for 40-60% of the time. When soot is present, it is observed as thin sheets which become narrower in regions where the average strain rate is estimated to be greater.

Additional Information

© 1987 Combustion Institute, Published by Elsevier Science Publishing Co., Inc. Received 5 May 1986; revised 24 July 1986. Available online 7 August 2003. The authors thank Prof. P. Dimotakis for suggesting the soot-scattering imaging technique, Prof. E. Zukoski for useful discussions on buoyancy-dominated flames, and both for critical reading of and suggestions on the manuscript. This work was sponsored by the Gas Research Institute under grant number 5083-260-0878. The linear camera and computer data-acquisition system used in this investigation were developed under the sponsorship of the Air Force Office of Scientific Research with primary contributions from Dr. Daniel B. Lang under contract number F49620-79-C-0159 and grant number AFOSR-83-0213.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023