Characteristics of jet flame in the wake

• Main Authors: Chou, Chen-Gi, 周春吉
• Other Authors: Muh-Rong Wang
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/31107130035739900081

碩士 === 國立成功大學 === 航空太空工程學系 === 84 === Comparison of the flame characteristics of "jet flame" and "jet flame in the wake" is carried out in this research. Results show that the temperature of "jet flame in the wake" is higher than "jet flame", implying that the "jet flame in the wake" has a better combustion conversion efficiency. On the other hand, the existence of wake flame of "jet flame in the wake" provides heat source to stabilize the flame. Measurements of concentration of combustion products also show the same trend. The turbulence intensity and wake intensity of "jet flame in the wake" increase with increase of Reynolds number. Under higher Reynolds number case, there is a better mix between fuel and air and a higher concentration in the wake. Therefore, there is a better combustion conversion efficiency under higher Reynolds number condition. The velocity of the fuel jet and Reynolds number also determine whether the combustion is primary in the wake or in the jet. Experiments also show that the interaction between jet and wake enhances the flame limit, e. g., the blow-off velocity of the "jet flame" is about 2m/s, but at the "jet flame in the wake" is about 18m/s. This indicates that the flame stability limit can be improved in the conventional combustion device by providing an extra flameholding mechanism.