Droplet Dynamics in Cooling Tower Plumes

Large cooling towers are becoming more common as a means of disposing of large quantities of waste heat from steam electric generating stations. Increased attention is being focused on how the effluents from these towers affect the environment. This research is concerned with the determination of the paths and ultimate deposition of salt laden drift drops exiting from a cooling tower by analyzing the basic droplet dynamics governing the transport of these droplets.

The equation of motion is developed for a liquid drift drop as it is transported through the atmosphere. A term appears in the equation of motion which has not been considered by previous authors. A finite difference technique is used to solve for the velocity and position of the drift drop at any time. Meteorological variables as well as cooling tower variables are considered in calculating the trajectory of the drift drop. A model is developed to account for the effects of dissolved chemicals on droplet evaporation rate.

The concepts presented in this paper have been incorporated into a model which predicts chemical deposition from evaporative cooling towers. The results of the model study show better agreement with experimental data than previous models.