Journal of Korean Society of Environmental Engineers (대한환경공학회지)

Korean Society of Environmental Engineers (대한환경공학회)
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A Study on Applicability of Coagulant Mixer and Flow Analysis of the Non-powered Vortex Mixer using CFD

전산유체역학(CFD)을 이용한 무동력 와류 혼화장치의 유동해석 및 응집제 혼화장치 적용 가능성 연구

  • Kim, Soo Yeon (Department of Civil & Environmental Engineering, Hanbat National University) ;
  • Chae, Jong Seong (Department of Civil & Environmental Engineering, Hanbat National University) ;
  • Kim, Sin Young (Department of Civil & Environmental Engineering, Hanbat National University) ;
  • Zhang, Meng Yu (Department of Civil & Environmental Engineering, Hanbat National University) ;
  • Ohm, Tea In (Department of Civil & Environmental Engineering, Hanbat National University)
  • 김수연 (국립한밭대학교 건설환경공학과) ;
  • 채종성 (국립한밭대학교 건설환경공학과) ;
  • 김신영 (국립한밭대학교 건설환경공학과) ;
  • 장몽우 (국립한밭대학교 건설환경공학과) ;
  • 엄태인 (국립한밭대학교 건설환경공학과)
  • Received : 2017.09.25
  • Accepted : 2017.12.20
  • Published : 2017.12.31
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Abstract

This study compared and analyzed the water treatment efficiency and the applicability of water treatment plant using the existing Mechanical Rapid-Mixer by introducing the Non-powered Vortex Mixer to the domestic water treatment plant. For this study, fluid flow characteristics and head loss of a Non-powered Vortex Mixer are calculated by Computational Fluid Dynamics (CFD)respectively. The head loss rate inside the mixer was 11.30% when the inflow velocity was 0.5 m/sec, 16.27% at 0.6 m/sec and 21.44% at 0.7 m/sec, the head loss rapidly increased at the optimal velocity of 0.5 m/sec. For the inflow velocity of 0.5 m/sec, the turbulent intensity at the inlet was 2.37% and at the outlet was 7.83%, so there was sufficient mixing strength for the particulate matter and the coagulant. The result of the water quality of the treatment plants with the inflow velocity of 0.38 m/sec that was operated in three years after replacing all 12 units of the existing Rapid-Mixer with the Non-powered Mixer met the standards. Hence, it is possible to reduce the energy consumption of 64,143 ~ 65,306 kWh/year since the Rapid-Mixer is replaced by the Non-powered Vortex Mixer.

본 연구는 국내 정수장에 무동력 와류 혼화장치를 설치하여 기존 기계식 급속혼화장치를 사용하는 정수장의 수처리 효율 및 적용 가능성을 비교 분석하였다. 이를 위해 무동력 와류 혼화장치의 유체 유동 특성 및 손실수두를 전산유체역학(CFD)으로 계산하였다. 혼화장치 내부의 수두손실률은 유입속도가 0.5 m/sec일 때 11.30%, 0.6 m/sec일 때 16.27%, 0.7 m/sec일 때 21.44%로 유입속도가 증가할수록 수두손실이 급격하게 증가하며 혼화지 설계 시 최적 유입 유속는 0.5 m/sec이다. 0.5 m/sec일 때 난류강도는 입구는 2.37%, 출구는 7.83%로 응집을 위한 혼화강도는 충분하다. 유입수의 유속이 0.38 m/sec인 정수장의 기계식 급속혼화장치 12대를 모두 무동력 와류 혼화장치로 대체하여, 3년 동안 운전한 정수장의 수질 검사결과는 기존의 급속혼화장치를 운전하는 정수장과 수질 차이가 없었으며 수질 기준에 적합하였다. 기존의 급속혼화장치를 무동력 혼화장치로 교체하면 1대당 동력소비량 64,143~65,306 kWh/y의 에너지를 절감할 수 있다.

Keywords

Acknowledgement

Grant : 다부처공동기획

Supported by : 환경부, Non-CO2온실가스 저감기술개발 사업단

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