应变速率、局部熄灭和流体力学不稳定性对附着和上升涡流火焰过渡的影响

2019/12/11   下载量： 0 次

方案摘要

方案下载
应用领域 能源/新能源
检测样本 其他
检测项目
参考标准 暂无

采用LaVision的时间分辨激光诱导荧光火焰分析系统FlameMaster-TR和2D3C时间分辨立体PIV测速系统，对应变速率、局部熄灭和流体力学不稳定性对附着和上升涡流火焰过渡的影响进行了实验测量研究。

方案下载
配置单
方案详情

The coupling between fluid strain rate, local flame extinction, hydrodynamic instability, and flame lift- offwas studied in premixed swirl flames using multi-kHz repetition-rate OH ∗chemiluminescence (CL), OH planar laser induced fluorescence (PLIF), and stereoscopic particle image velocimetry (S-PIV). Over 50 different combinations of fuel composition (CH 4 /H 2 ratio), equivalence ratio, and reactant preheat temper- ature were studied, allowing systematic variation of the reactant-to-product density ratio, laminar flame speed, and Lewis number. Depending on the test conditions, the flame could either be stably attached to the nozzle, stably lifted, or intermittently transitioning between attached and lifted states. Transition between stabilization states was linked with the transition between convective instability and absolute instability at the flame base; formation of an m = 1 ( m denotes the azimuthal wavenumber) globally un- stable wave was associated with the lifted flame, which was manifested by a helical precessing vortex core (PVC). The minimum bulk velocity at which the flame was stably lifted was linearly correlated with the laminar flame extinction strain rate, while none of the other commonly reported key parameters gov- erning hydrodynamic instability was able to collapse the data alone. Hence, lift-offwas associated with a relatively constant Damköhler number based on the bulk fluid strain rate and extinction strain rate. The roles of local strain and extinction on the transition process were further elucidated by the cases with in- termittent lift-off/reattachment. The probability of the flame being in the lifted state was roughly linearly correlated with the degree of local extinction at the flame base while the flame was still in the attached state. Moreover, this probability also was linearly related to the ratio of fluid-dynamic strain rate to ex- tinction strain rate, but not the fluid-dynamic strain rate itself. These results demonstrate the importance of predicting extinction and hydrodynamic stability for predicting the attachment state of swirl flames.

上一篇 在一个双稳湍流涡旋火焰中，对间歇性动态的时间-频率定位
下一篇 利用多平面PIV技术研究两种原型设计的进气道的涡流和滚流

文献贡献者

北京欧兰科技发展有限公司
金牌会员 丨 第17年
查看全部资料
推荐方案
更多

相关产品

当前位置： 仪器信息网 欧兰科技 方案 应变速率、局部熄灭和流体力学不稳定性对附着和上升涡流火焰过渡的影响

关注

拨打电话

留言咨询