Report of Investigations 8263: The Diffusion Flame in Free Convection: Buoyancy-Induced Flows, Oscillations, Radiative Balance, and Large-Scale Limiting Rates

Details

• Personal Author:
  Burgess, David S. ; Cashdollar, Kenneth L. ; Hertzberg, Martin ; Litton, Charles D.
• Corporate Authors:
  United States. Bureau of Mines
• Description:
  This Bureau of Mines report describes experimental and theoretical studies of diffusion flames in free convection. The cross-coupling between buoyancy-induced flows and the combustion process is explored as it relates to the size, structure, and radiative balance of flames. New data are presented for the size-dependent radiance oscillations of diffusion flames and for the angular distribution of the total radiant intensity from a small methanol pool flame. Both amplitude and frequency of the measured oscillations are compared with theoretical predictions that are based on a new view of the structure of diffusion flames. This new view, which is at variance with the traditional one, assumes uniform reaction in the diffusive mixing zone, and recognizes the significance of the role played by convective buoyancy and its duality in both aiding and impeding flame propagation. Buoyancy quenches propagation at low burning velocities, introducing a real discontinuity in the combustion rate. A "flammable volume" is thus defined as that bound between lean- and rich-limit contours. However, in the flow disturbances generated by combustion waves that consume that volume, buoyancy aids propagation by promoting the convective mixing of a new flammable volume. The measured radiance oscillations are manifestations of these propagation and remixing cycles. [Description provided by NIOSH]
• Subjects:
  Fires Mining Occupational Health Safety
• Series:
  Mining Publications
• Subseries:
  Report of Investigations
• ISSN:
  1066-5552 (print)
• Publisher:
  United States. Bureau of Mines
• Document Type:
  Text
• Genre:
  Case Report
• Rights:
  Public Domain
• CIO:
  National Institute for Occupational Safety and Health (NIOSH)
• Division:
  PRC - Pittsburgh Research Center
• Topic:
  Workplace Safety & Health
• Location:
  North America
• Pages in Document:
  42 pdf pages
• Contributor:
  Strasser, Alex
• NIOSHTIC Number:
  nn:10000427
• NTIS Accession Number:
  PB-277250
• Citation:
  NTIS: PB 277 250; :1-33
• Federal Fiscal Year:
  1978
• Peer Reviewed:
  False
• Source Full Name:
  NTIS: PB 277 250
• Collection(s):
  National Institute for Occupational Safety and Health
• Main Document Checksum:
  urn:sha-512:6ec1b03b687e11814c64743c03f48e8814aabd6f687c593a3f0be21c88c9f224dca26f47f45064dee99caa88ba5b2e16af121ce12045981dce305206f2251276
• Download URL:
  https://stacks.cdc.gov/view/cdc/201700/cdc_201700_DS1.pdf
• File Type:
  [PDF - 1.93 MB ]