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ALOFT-FTTM Smoke Plume Trajectory Model for Personal Computers
ALOFT-FTTM (A Large Outdoor Fire plume Trajectory model - Flat Terrain) is a computer based model to predict the downwind distribution of smoke particulate and combustion products from large outdoor fires. Measurements and observations at experimental fires have shown that the downwind distribution of smoke is a complex function of the fire parameters, meteorological conditions and topographic features. To incorporate these features, NIST has developed a smoke plume trajectory model that solves the fundamental fluid dynamic equations for the smoke plume and its surroundings. ALOFT-FT is the public domain version of the model for flat terrain using windows based personal computers. The program contains a graphical user interface for input and output and a user modifiable database of fuel and smoke emission parameters. The output can be displayed as downwind, crosswind and vertical smoke concentration contours. Information on using the program is available with on-line help commands in the program.
ALOFT-FT was developed to aid in the planning process for the intentional burning of crude oils spills on water. The program may also be useful in predicting the smoke plume trajectory from other large outdoor fires particularly liquid pool fires
Most smoke plume models use relatively simple correlations to describe a smoke plume. These correlations usually produce a Gaussian profile of downwind smoke concentration. While these models may be useful in some circumstances, measurements and observations at experimental burns have shown that the downwind distribution of smoke is not Gaussian. The simple smoke plume models do not capture the observed plume features such as the twin counter-rotating vortices frequently observed. ALOFT-FT solves the fundamental Navier-Stokes equations using an eddy viscosity over a uniform grid which spans the smoke plume and its surroundings. The model inputs include wind speed and variability, atmospheric temperature profile, number of fires, fuel parameters and emission factors. The output is the average concentration of combustion products in each of the computational cells from ground level to the top of the plume. The output can be displayed as downwind, crosswind and vertical concentration contours.
Input Screen for Fire Parameters
Input Screen for Wind Parameters
Input Screen for Temperature Parameters
Input Screen for Fuel Parameters
Summary Output Screen
Horizontal Concentration Output Screen
Downwind Vertical Concentration Output Screen
Vertical Crosswind Concentration Output Screen
Temperature Profile Output Screen