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Three dimensional Eulerian-Eulerian simulation on hydrodynamics in dissolved air flotation tank with different
Baoqing Deng1, Qiong Ding1, Daqiang Ge1
1Department of Environmental Science and Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China
Summary
This study simulates dissolved air flotation (DAF) tanks using a 3D Eulerian-Eulerian model. The RNG k-ɛ turbulence model and small air bubbles optimize suspended matter removal in DAF systems.
Area of Science:
- Fluid Dynamics
- Chemical Engineering
- Environmental Engineering
Background:
- Dissolved air flotation (DAF) is crucial for water treatment.
- Accurate simulation of two-phase flow in DAF tanks is challenging.
- Understanding flow patterns and bubble behavior is key to optimizing DAF performance.
Purpose of the Study:
- To simulate two-phase air-water flow in a DAF tank using the Eulerian-Eulerian approach.
- To evaluate different turbulence models for accuracy.
- To investigate the impact of air bubble size on DAF efficiency.
Main Methods:
- Utilized an unsteady, three-dimensional Eulerian-Eulerian simulation.
- Compared four two-equation turbulence models, focusing on the RNG k-ɛ model.
- Simulated the effect of varying air bubble diameters on DAF performance.
Main Results:
- The 3D model successfully reproduced experimental stratification structures.
- The RNG k-ɛ turbulence model showed the best agreement with experimental data.
- Smaller air bubbles created a larger high-volume fraction zone, enhancing pollutant removal.
Conclusions:
- The 3D Eulerian-Eulerian approach with the RNG k-ɛ model accurately simulates DAF tanks.
- Optimizing air bubble size is critical for efficient suspended matter removal in DAF.
- This simulation provides valuable insights for DAF tank design and operation.
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