Numerical simulation of near-surface environments and particulate clouds generated by large-area fires. Technical report, 3 November 1982-22 December 1986

Technical Report · Mon Aug 24 00:00:00 EDT 1987

OSTI ID:5413607

Marcus, S L; Krueger, S K; Rosenblatt, M

The near-surface environments and lofted particulate clouds produced by large-area fires were simulated with the axisymmetric DICE code. Studies with an inviscid version of the model showed that variations in the assumed area and burning rate of the fire have a strong effect on the maximum inflow winds, temperatures, and plume heights that develop. Using a multiphase version of the model, which predicts concentrations of soot, water vapor, liquid water, and ice, it was found that the particulate clouds generated by large-area fires show considerable vertical dispersion, and that latent heat released by condensing water vapor can significantly enhance cloud heights. When the grid is changed from finely zoned to coarsely zoned, the effective mixing of the combustion heating over a greater depth generates cooler maximum temperatures, causing the plume to shift from oscillatory (overshooting) behavior to a steady-state regime. When the mixing is explicity accounted for by introducing parameterized turbulence, steady-state behavior results for the finely zoned cases as well. Using an extended version of DICE that includes a tangential velocity component, an initial swirl velocity of 10 m/sec at the edge of a 10-km radius fire was found to spin up to swirl velocities in excess of 200 m/sec in the inflow layer near the axis of the fire. Plume heights for this case, which allowed no interaction of swirl with turbulence, were about 3-km lower than a corresponding nonrotating case.

• Research Organization: California Research and Technology, Inc., Chatsworth (USA)
• OSTI ID: 5413607
• Report Number(s): AD-A-188375/0/XAB; CRT-3880F
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AIR POLLUTION
PARTICULATES
PLUMES
FIRES
MATHEMATICAL MODELS
CLOUDS
COMBUSTION
GRIDS
HEATING
ICE
LAYERS
LIQUIDS
NUMERICAL ANALYSIS
PROGRESS REPORT
SURFACES
TURBULENCE
VELOCITY
WATER
WATER VAPOR
WIND
CHEMICAL REACTIONS
DOCUMENT TYPES
ELECTRODES
FLUIDS
GASES
HYDROGEN COMPOUNDS
MATHEMATICS
OXIDATION
OXYGEN COMPOUNDS
PARTICLES
POLLUTION
THERMOCHEMICAL PROCESSES
VAPORS
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)