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Numerical Study of Effect of DAF-Tank Shape on Flow Pattern in Separation Zone of Dissolved Air Flotation

용존공기부상조(DAF-tank)의 형상변화가 분리조(Separation Zone)의 내부 유동 패턴에 미치는 영향에 대한 수치해석적 연구

  • Ryu, Gwang-Nyeon (Industrial Research Inst., R&D Div., Hyundai Heavy Industries) ;
  • Park, Sang-Min (Industrial Research Inst., R&D Div., Hyundai Heavy Industries) ;
  • Lee, Ho-Il (Industrial Research Inst., R&D Div., Hyundai Heavy Industries) ;
  • Chung, Mong-Kyu (Industrial Research Inst., R&D Div., Hyundai Heavy Industries)
  • 류광년 (현대중공업 기술개발본부 산업기술연구소) ;
  • 박상민 (현대중공업 기술개발본부 산업기술연구소) ;
  • 이호일 (현대중공업 기술개발본부 산업기술연구소) ;
  • 정몽규 (현대중공업 기술개발본부 산업기술연구소)
  • Received : 2010.12.10
  • Accepted : 2011.06.21
  • Published : 2011.08.01

Abstract

We numerically simulated a dissolved air flotation (DAF) tank to predict the performance of the pilot facility. The flow was assumed to be two-dimensional and two-phase. The velocity distributions in the separation zones of differently shaped DAFs were compared to find the effect of the shape on the performance. The results showed that the typical flow pattern that appeared in a well-designed DAF-tank was generated in the separation zone of the base model. This flow pattern could be maintained while the baffle height was sufficiently tall regardless of the other geometric parameters. However, the baffle height and angle, the contact zone width, and the perforated plate affected the uniformity of the downward flow in the separation zone. Except for the baffle height, the base model used in this study showed a better uniformity of downward flow than did other models with different geometric parameters.

용존공기부상조의 파일럿실험장치 설계를 위한 사전 검증 작업으로서 부상조의 유동을 이차원 이상유동으로 가정하여 수치적으로 모사하였다. 형상이 변경된 다양한 부상조와 기준부상조와의 간접적인 성능 비교를 위하여 분리조에서의 하강속도를 비교하였다. 해석 결과 기준부상조의 분리조에서는 잘 설계된 High-rate DAF 의 전형적인 유동 패턴이 관찰되었다. 이러한 유동패턴은 Baffle 각도나 접촉조의 폭과 같은 다른 형상 변수와 상관없이 Baffle 이 충분히 높을 때 잘 유지되었다. 그러나 Baffle 높이 및 각도, 접촉조의 폭 및 다공판의 설치유무는 분리조에서 하강속도의 균일성에 영향을 미쳤다. 기준부상조에서 Baffle의 높이를 제외한 다른 형상을 변화시키지 않았을 때, 분리조에서의 하강속도가 균일한 것으로 나타났다. 이것은 기준부상조의 형상최적화가 잘 되어있음을 의미한다.

Keywords

References

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