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Examining the effect of length/width ratio on the hydro-dynamic behaviour in a DAF system using CFD and ADV techniques.
- Source :
-
Water Science & Technology . 2006, Vol. 53 Issue 7, p141-149. 9p. - Publication Year :
- 2006
-
Abstract
- Dissolved air flotation (DAF) is a solid-liquid separation system that uses fine bubbles rising from the bottom to remove particles in water. In this study, we investigated the effect of L/W (L; length, W; width) on the hydrodynamic behavior in a DAF system using CFD (computational fluid dynamics) and ADV (acoustic Doppler velocimetry) technique. The factual full-scale DAF system, L/W ratio of 1:1, was selected and various L/W ratio conditions (2:1, 3:1, 4:1 and 5:1) were simulated with CFD. For modelling, 2-phase (gas-liquid) flow equations for the conservation of mass, momentum and turbulence quantities were solved using a Eulerian-Eulerian approach based on the assumption that a very small particle is applied in the DAF system. Also, for verification of CFD simulation results, we measured the actual velocity at some points in the full-scale DAF system with the ADV technique. Both the simulation and the measurement results were in good accordance with each other. We concluded that the L/W ratio and outlet geometry play an important role for flow pattern and fine bubble distribution in the flotation zone. In the ratio of 1:1, the dead zone is less than those in other cases. On the other hand, in the ratio of 5:1, the fine bubbles were more evenly distributed. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02731223
- Volume :
- 53
- Issue :
- 7
- Database :
- Academic Search Index
- Journal :
- Water Science & Technology
- Publication Type :
- Academic Journal
- Accession number :
- 23886552
- Full Text :
- https://doi.org/10.2166/wst.2006.218