Boundary Layer Flashback in Premixed Hydrogen-Air Flames With Acoustic Excitation
Boundary Layer Flashback in Premixed Hydrogen-Air Flames With Acoustic Excitation
复制标题
声激励预混氢气-空气火焰中的边界层回火
DOI：
10.1115/1.4038128
复制
发表时间：
2018
影响因子：
1.5
通讯作者：
Sattelmayer
中科院分区：
文献类型：
--
作者：
Hoferichter;Sattelmayer
稀薄预混合燃烧在燃气轮机中占主导地位，以最大限度地减少氮氧化物排放。然而，这种技术承担着火焰回火和热声不稳定的风险。热声不稳定性引起燃烧器出口处的速度振荡，这反过来又可以触发火焰回火。本文介绍了在环境条件下纵向声激励对通道式燃烧器边界层回火影响的实验研究。声激励模拟热声不稳定性的影响。确定了表征典型燃气涡轮机燃烧室（100 - 350 Hz）中频动态特性的不同激励频率的回火极限。激励幅值在燃烧器总流速的0%至36%之间变化。随着激励幅值的增加，火焰回火的风险增加。这种效应在低频时最强。随着激励频率的增加，速度振荡的影响减小，因为火焰有更少的时间来跟随整体流动速度的变化。两种不同的回火状态可以基于激励幅度来区分。对于低激发振幅，如果激发循环中的最小流速福尔斯低于未激发的无约束火焰的回火极限，则达到回火条件。对于较高的激发振幅，其中火焰开始周期性地进入燃烧器管道，如果激发循环中的最大流速低于受限火焰的回火极限，则回火开始。因此，在燃气涡轮机燃烧器的设计中，还应将受限火焰的回火限制作为最坏情况考虑。
Lean premixed combustion is prevailing in gas turbines to minimize nitrogen oxide emissions. However, this technology bears the risk of flame flashback and thermoacoustic instabilities. Thermoacoustic instabilities induce velocity oscillations at the burner exit which, in turn, can trigger flame flashback. This article presents an experimental study at ambient conditions on the effect of longitudinal acoustic excitation on flashback in the boundary layer of a channel burner. The acoustic excitation simulates the effect of thermoacoustic instabilities. Flashback limits are determined for different excitation frequencies characterizing intermediate frequency dynamics in typical gas turbine combustors (100–350 Hz). The excitation amplitude is varied from 0% to 36% of the burner bulk flow velocity. For increasing excitation amplitude, the risk of flame flashback increases. This effect is strongest at low frequencies. For increasing excitation frequency, the influence of the velocity oscillations decreases as the flame has less time to follow the changes in bulk flow velocity. Two different flashback regimes can be distinguished based on excitation amplitude. For low excitation amplitudes, flashback conditions are reached if the minimum flow velocity in the excitation cycle falls below the flashback limit of unexcited unconfined flames. For higher excitation amplitudes, where the flame starts to periodically enter the burner duct, flashback is initiated if the maximum flow velocity in the excitation cycle is lower than the flashback limit of confined flames. Consequently, flashback limits of confined flames should also be considered in the design of gas turbine burners as a worst case scenario.
登录
查看更多内容
影响因子：
1.3
作者：
L. N. Khitrin;P. Moin;D. B. Smirnov;V. Shevchuk
通讯作者：
V. Shevchuk
DOI：
10.1115/1.4031227
发表时间：
2016-02-01
影响因子：
1.5
作者：
Baumgartner, Georg;Boeck, Lorenz R.;Sattelmayer, Thomas
通讯作者：
Sattelmayer, Thomas
影响因子：
1.3
作者：
Hoferichter, Vera;Hirsch, Christoph;Sattelmayer, Thomas
通讯作者：
Sattelmayer, Thomas
DOI：
10.1115/1.4034237
发表时间：
2017-02-01
影响因子：
1.5
作者：
Hoferichter, Vera;Hirsch, Christoph;Sattelmayer, Thomas
通讯作者：
Sattelmayer, Thomas
高速Micro-PIV和Micro-PLIF结合化学发光成像的通用预混燃烧系统从稳定火焰到回火的过渡机制的实验研究
影响因子：
4.4
作者：
G. Baumgartner;L. R. Boeck;T. Sattelmayer
通讯作者：
T. Sattelmayer