|
KMID : 0895420050150010036
|
|
Journal of Korean Society of Occupational and Enviromental Hygiene
2005 Volume.15 No. 1 p.36 ~ p.44
|
|
|
Evaluation of Capture Efficiencies of Push-Pull Hood Systems by Cross Draft Directions and Velocities Using Smoke Visualization Technique
|
|
Song Se-Wook
Kim Tae-Hyeung
Ha Hyun-Chul
Kang Ho-Gyung
|
|
|
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 ±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.
|
|
|
KEYWORD
|
|
|
Push-pull hood, Cross draft, Open surface tank, pickling and plating, smoke visualization
|
|
|
FullTexts / Linksout information
|
|
|
|
|
|
Listed journal information
|
|
|
|