- Author
-
Grinberg, I. M.
|
Putnam, A. A.
- Title
- Model Study of the Interaction Effects of Mass Fires. Summary Report No. 3.
- Coporate
- National Bureau of Standards, Gaithersburg, MD
Battelle Memorial Inst., Columbus, OH
- Report
-
Summary Report No. 3,
September 28, 1964,
50 p.
- Contract
- NBS-CST-1104
- Keywords
-
mass fires
|
model studies
|
temperature measurements
- Abstract
- As analytical expression has been formulated which correlates the temperature profile of a turbulent diffusion, buoyancy-controlled flame to fuel properties and flow conditions. The expression derived is based on the principle that, in order for flame to be similar, the turbulent shear forces and buoyancy forces must be in a constant ratio. It is valid in the region after combustion is completed, and is valid at higher temperature levels than previously used correlations which are accommodated as a limiting case. In the correlation, the variation of temperature of the flame with height is expressed as a function of the stoichiometric air-fuel ratio, the fuel flow rate, the adiabatic flame temperature, and ambient conditions of air temperature and density. The expression predicts a more rapid decrease in temperature immediately after combustion is completed than do previous theories based on the assumption of small density differences between the turbulent plume and the ambient atmosphere. At distances far from the flame, as the plume temperature approaches that of the surrounding atmosphere, the related theory predicts a temperature profile that asymptotically approaches that conventionally obtained (by theory based on small density differences). The correlation was supported experimentally by using fuels of different diameters. It was satisfactorily applied even to flames that were partially thrust controlled as determined from visible flame-height measurements.