Journal of Korean Society of Occupational and Environmental Hygiene (한국산업보건학회지)

Korean Industrial Hygiene Association (한국산업보건학회)
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Evaluation of Capture Efficiencies of Push-Pull Hood Systems by Cross Draft Directions and Velocities Using Smoke Visualization Technique

기류 가시화기법을 이용한 방해기류 방향과 속도에 따른 푸쉬풀 후드 효율 평가

  • Song, Se-Wook (Korea Occupational Safety & Health Agency) ;
  • Kim, Tae-Hyeung (Department of Environmental Engineering Changwon National University) ;
  • Ha, Hyun-Chul (Department of Environmental Engineering Changwon National University) ;
  • Kang, Ho-Gyung (Department of Environmental Engineering Changwon National University)
  • Received : 2004.11.06
  • Accepted : 2005.03.03
  • Published : 2005.03.30
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Abstract

A push pull hood system is frequently applied to control contaminants evaporated from an open surface tank in recent years. Efficiency of push pull hood system is affected by various parameters, such as cross draft, vessel shapes, size of tanks surface, liquid temperature, and so on. Among these, velocity of cross draft might be one of the most influencing factor for determining the ventilation efficiency. To take account of the effect of cross draft velocities over 0.38m/s, a flow adjustment of ${\pm}$20% should be considered into the push and +20% into the pull flow system Although there are many studies about the efficiency evaluation of push pull hood system based on CFDs(Computational Fluid Dynamics) and experiments, there have been no reports regarding the influence of velocities and direction of cross-draft on push-pull hood efficiency. This study was conducted to investigate the influence of cross draft direction and velocities on the capture efficiency of the push-pull ventilation system. Smoke visualization method was used along with mock-up of push-pull hood systems to verify the ventilation efficiency by experiments. When the cross-draft blew from the same origins of the push flows, the efficiency of the system was in it's high value, but it was decreased significantly when the cross-draft came from the opposite side of push flows Moreover, the efficiency of the system dramatically decreased when the cross-draft of open surface tank was faster than 0.4m/s.

Keywords

Acknowledgement

Supported by : 한국과학재단

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