NUMERICAL MODELING OF FLOW IN CHLORINE DISINFECTION TANKS

The reliability of simulations of flow and disinfection processes in d isinfection contact tanks is determined by the accuracy of computation s in terms of the hydrodynamic characteristics in the tanks, particula rly the accuracy of the calculations of advection and shear stress, wh ich are two problematic terms currently under intensive research. As p art of the development of a simulation module for a software package o f flow and disinfection process predictions in chlorine contact tanks, various modeling methods and difference schemes have been tested for typical tank configurations, and the results are compared and analyzed . In the software the computation of shear stress terms was originally represented by a depth mean viscosity model, and its results have bee n compared with that of calculations using the (k) over bar-<(epsilon) over bar> and the Smagorinsky subgrid scale stress models in an attemp t to improve upon the model predictions. The discretization of advecti on terms in the software module was a first-order upwind difference sc heme, the results of which also have been compared with that of its tw o alternatives, the QUICK scheme and a third-order upwind difference s cheme. Predictions made by using several combinations of these models and schemes were tested against measurements from a physical model stu dy.