Study of influence of natural convection on push-pull air curtain

• Main Authors: Yi-Wen LAI, 賴藝文
• Other Authors: Ming-Jyh Chern
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/21058511379934095520

碩士 === 國立臺灣科技大學 === 機械工程系 === 97 === The aim of this study is to investigate the influence of heat source with a large area in a push-pull fume hood. We used the application of the flow visualization method to observe flow variation due to the influence of temperature gradient. Meanwhile we employed a commercial software to simulate the problem. The airflow in the hood and the deformation of the air curtain due to the heat source are simulated. The results of this experiment reveals that the push-pull air curtain is deformed as the temperature gradient increases. It is found that the push-pull air curtain loses capability of capturing as Archimedes number is higher then 0.3, Moreover, numerical results reveal that there is a large vortex inside the hood due to influence of natural convection. The vortex exists for a variety of speed ratios of push-pull flows and temperature gradient in the push-pull fume hood. The results of the airflow patterns can be used as guidelines for the appropriate operation of a push-pull fume hood.