CFD prediction of cooling tower drift

Drift of small water droplets from mechanical and natural draft cooling tower installations can contain water treatment chemicals such that contact with plants, building surfaces and human activity can be hazardous. Prediction of drift deposition is generally provided by analytic models such as the US Environmental Protection Agency approved Industrial Source Complex Short Term Version 3 (ISCST3) or Seasonal-Annual Cooling Tower Impact (SACTI) codes; however, these codes are less suitable when cooling towers are located midst taller structures and buildings. A computational fluid dynamics (CFD) code including Lagrangian prediction of the gravity driven but stochastic trajectory descent of droplets is considered and compared to data from the 1977 Chalk Point Dye Tracer Experiment. The CFD program predicts plume rise, surface concentrations, plume centerline concentrations and surface drift deposition within the bounds of field experimental accuracy.