AWWA ACE63048

Maintaining adequate water quality is a chief criterion when designing andretrofitting water storage and mixing facilities (e.g. reservoirs, mixing tanks, contact chambers,etc.). Common problems associated with a poor design include: hydraulic short-circuiting;formation of dead zones; poor circulation; and, excessive detention time. The design ofsuch a facility requires the engineer to favorably locate and orient inlet and outlet structures (andpossibly baffle systems and mixers). Until recently, the only method for reliably evaluatingdesign alternatives was to perform a laboratory/field tracer study (i.e. physically injecting dyeinto the system, observing the overall dye pattern, and sampling at the outlet). Today, analternative to the laboratory/field tracer study exists a numerical tracer test performed on acomputer using a computational fluid dynamics (CFD) model. A CFD model supplies theengineer with a "virtual laboratory" for testing and optimization providing the ability to screennumerous design alternatives and converge on a favorable system design.In this study, two commercially available CFD models are used to numerically evaluatereservoir mixing characteristics. To build confidence in the numerical results, the CFD modelswere first applied to the following verification/validation cases: a free-jet; a 180-degreesharp bend; and, a rectangular tank with a baffle wall. As part of the validation studies, theCFD results were compared with analytical solutions, experimental data, and laboratory tracerstudies. Next, the CFD models were applied to two "real world" projects where the model resultswere used to help evaluate design alternatives. The information presented herein will assistengineers in applying CFD models to other water storage and mixing facilities. Includes figures.

Product Details

Edition:

Vol. - No.

Published:

06/01/2006

Number of Pages:

18

File Size:

1 file , 1.3 MB