| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 96 === The aim of this study is to investigate robustness of the conventional and push-pull fume hoods using numerical approaches. We consider three the followings situations. The first one is the arm effect.
The second is the effect of moving arm. The last one is the walk-by effect.
In this study, we use two commercial software based on the finite volume and finite element methods to simulation these problems. One uses the finite volume method, the other uses the finite element method. We also use standard k-εturbulence model to describe characteristics of a turbulent flow. In the study of the arm effect, we find that the conventional fume hood is unable to capture pollutants. On the other hand, we find that the push-pull fume hood is not affected by the arm effect. In the effect of moving arms, we find that moving hands generates some vortices in the push-pull fume hood cupboard.
However, the air curtain is still robust and pollutants can be captured by the capture. In the study of walk-by effect, we find the ability of push-pull fume hood to capture pollutant is better than the conventional fume hood. The pollutant concentration in the conventional fume hood is more than 100 times the standard. Finally, we propose the range for combination of push and pull flows in which the air curtain can resist the vortex effect due to walk-by.
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