摘要
为探索大型电站锅炉横向再燃射流的穿透性,采用大涡模拟方法分别计算了射流速度比率为10的横向圆管湍流射流和椭圆湍流射流,基于射流速度50 m/s的雷诺数为16600.模拟结果表明,圆管射流中心轨迹与试验数据基本一致,方向因子为0.3的椭圆射流的穿透能力远大于圆管射流穿透力.计算捕捉到了射流上游由开尔芬-亥姆霍兹不稳定性引起的剪切层涡卷、始于近场并主宰远场的逆向旋转涡对和圆管射流尾涡区的垂直上升尾涡.与圆管射流相比,椭圆射流的剪切层涡卷的强度大大减弱,逆向旋转涡对狭长对称,尾涡区的垂直上升尾涡并不明显,这是椭圆射流穿透力提高的主要原因.
Large eddy simulation （LES） was employed to simulate a round turbulent jet and an elliptic turbulent jet in cross flow respectively with the velocity ratio of 10 to investigate the penetrability of the transverse reburn jet in large capacity boilers. The Reynolds number based on the jet velocity of 50 m/s was 16 600. Numerical results of the trajectory showed good agreement with experimental data. The penetrability of the elliptic jet with the aspect ratio of 0.3 was much stronger than that of the round jet. Simulation captured the dominating vortex systems. Kelvin-Helmholtz instability induced shear layer vortical roller, counter-rotating vortex pair （CVP） which begins in the near-field and dominates the far-field, and upright vortex in the wake. Compared with the round jet, the relatively lower intensity of the shear layer vertical roller of the elliptic jet, the long and narrow shape of the symmetrical CVP and the absence of the upright vortex in the wake were the main reasons for the strong penetrability of the transverse elliptic jet.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2007年第7期1181-1185,共5页
Journal of Zhejiang University：Engineering Science
基金
国家自然科学基金资助项目(50576081
60534030)
关键词
横流
圆管射流
椭圆射流
大涡模拟
transverse flow
round jet
elliptic jet
large eddy simulation （LES）
