Journal of Korean Society of Water and Wastewater (상하수도학회지)

The Korean Society of Water and Wastewater (대한상하수도학회)
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Examining the Effect of L/W Ratio on the Hydro-dynamic Behavior in DAF System Using CFD & ADV Technique

전산유체역학과 ADV기술을 이용한 장폭비의 DAF조내 수리흐름에 미치는 영향 연구

  • 박노석 (한국수자원공사 수자원연구원) ;
  • 권순범 (한국수자원공사 수자원연구원) ;
  • 이선주 (한국수자원공사 수자원연구원) ;
  • 배철호 (한국수자원공사 수자원연구원) ;
  • 김정현 (한국수자원공사 수자원연구원) ;
  • 안효원 (한국수자원공사 수자원연구원)
  • Received : 2005.03.22
  • Accepted : 2005.07.19
  • Published : 2005.08.15
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Abstract

Dissolved air flotation (OAF) is a solid-liquid separation system that uses fine bubbles rising from bottom to remove particles in water. In this study, we investigated the effect of L/W (L; Length, W; Width) on the hydro-dynamic behavior in 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 (2:1, 3:1, 4:1 and 5:1) conditions were simulated with CFD. For modelling, 2-phase (gas-liquid) flow equations for the conservation of mass, momentum and turbulence quantities were solved using an Eulerian-Eulerian approach based on the assumption that very small particle is applied in the DAF system. Also, for verification of CFD simulation results, we measured the factual velocity at some points in the full-scale DAF system with ADV technique. Both the simulation and the measurement results were in good accordance with each other. As the results of this study, we concluded that L/W ratio and outlet geometry play 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 hands, in the ration of 3:1, the fine bubbles were more evenly distributed.

Keywords

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