Plume Rise

Various attempts have been made to estimate the plume rise from stationary sources. Two types of equations have resulted: theoretical and empirical. Theoretical models are generally derived from the laws of buoyancy and momentum. They are often adjusted for empirical data. Empirical models are developed from large amounts of ob

Distance from Source (m)

FIG. 5.8.7 Vertical dispersion coefficient as a function of downwind distance from the source. (Reprinted from Turner, 1970.)

Distance from Source (m)

FIG. 5.8.7 Vertical dispersion coefficient as a function of downwind distance from the source. (Reprinted from Turner, 1970.)

served data such as tracer studies, wind tunnel experiments, and photographic evidence. Most plume rise equations apply to uniform or smoothly varying atmospheric conditions. An important consideration is that while they often predict the plume rise reasonably well under similar conditions, they can give wrong answers for other conditions.

Momentum and Buoyancy Factors

The plume rises mainly due to two factors: 1) the velocity of the exhaust gas, which imparts momentum to the plume, and 2) the temperature of the exhaust gas, which gives the plume buoyancy in ambient air. The momentum flux comes from mechanical fans in duct systems and the

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