摘要
对不同空气旋流强度下气泡雾化喷嘴出口下游喷雾流场特性及燃烧特行进行了诊断与分析.随着空气旋流强度的增加,喷雾锥角明显增大,颗粒的轴向平均速度有所降低,而速度分布趋势则由单峰分布逐渐转变为双峰分布.同时,径向和切向的平均速度都有所提高,速度脉动加强,气、液两相之间的混合趋于强烈.空气旋流强度对油雾的燃烧过程影响显著,随着旋流数S的增大,油雾火焰的湍乱程度加强,火焰长度缩短,火焰表面皱褶和旋涡的尺度有所减小.空气旋流强度过小或过大,都将导致燃烧状况恶化;在S=1.2时,燃烧产物中的CxHy、CO和NO的体积含量均达到较低的水平.
Effects of air swirl intensity on atomization and combustion performance of effervescent atomized spray were investigated under different conditions. With the enhancing of swirl intensity, the mixing process between air and droplets is speed up. Therefore, the spray cone angle increases remarkably, the mean axial velocity decreases gradually, the radial velocity and tangential velocity increase slightly and the fluctuation velocity increases evidently. As a result, the profiles of axial velocity become a twin-peak curve. Air swirl intensity has a marked effect on spray flame. As the swirl number increases, the turbulent spray flame become more wobbly. The length of flame shortens obviously, but the scales of erimples and eddies on the surface of flame reduce moderately. As the swirl number S = 1.2, all the fractions of CxHy, CO and NO remain at a lower level. While too large or too small a swirl number will lead to the deterioration of combustion.
出处
《燃烧科学与技术》
EI
CAS
CSCD
北大核心
2008年第6期523-528,共6页
Journal of Combustion Science and Technology
基金
天津市应用基础及前沿技术研究计划资助项目(08JCZDJC22800)
关键词
旋流强度
气泡雾化喷嘴
流场
湍流
油雾火焰
swirl intensity
effervescent atomizer
flow field
turbulence
spray flame
