Drift modeling and monitoring comparisons

Abstract Ten drift deposition models are compared using a set of standard input conditions for a natural draft cooling tower. Most of the models agree within a factor of three. However when all ten models are compared, the predicted maximum drift deposition differs by two orders of magnitude, and the downwind locations of the maximum differ by one order of magnitude. The discrepancies are attributed mainly to different assumptions in the model regarding the initial effective height of the droplets. Current programs measuring drift characteristics at the tower mouth and drift deposition downwind of the tower are summarized. At the present time, drift deposition measurements, sufficiently comprehensive for model verifications, are unavailable. Hopefully, the Chalk Point Program will satisfy this need.