Maintaining adequate water quality is a chief criterion when designing and
retrofitting 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 of
such a facility requires the engineer to favorably locate and orient inlet and outlet structures (and
possibly baffle systems and mixers). Until recently, the only method for reliably evaluating
design alternatives was to perform a laboratory/field tracer study (i.e. physically injecting dye
into the system, observing the overall dye pattern, and sampling at the outlet). Today, an
alternative to the laboratory/field tracer study exists a numerical tracer test performed on a
computer using a computational fluid dynamics (CFD) model. A CFD model supplies the
engineer with a "virtual laboratory" for testing and optimization providing the ability to screen
numerous design alternatives and converge on a favorable system design.
In this study, two commercially available CFD models are used to numerically evaluate
reservoir mixing characteristics. To build confidence in the numerical results, the CFD models
were first applied to the following verification/validation cases: a free-jet; a 180-degree
sharp bend; and, a rectangular tank with a baffle wall. As part of the validation studies, the
CFD results were compared with analytical solutions, experimental data, and laboratory tracer
studies. Next, the CFD models were applied to two "real world" projects where the model results
were used to help evaluate design alternatives. The information presented herein will assist
engineers in applying CFD models to other water storage and mixing facilities. Includes figures.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 1.3 MB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 18 |
| Published : | 06/01/2006 |
