Effects of Nonuniform Reactant Stoichiometry on Thermoacoustic Instability in a Lean-Premixed Gas Turbine Combustor
Effects of Nonuniform Reactant Stoichiometry on Thermoacoustic Instability in a Lean-Premixed Gas Turbine Combustor
复制标题
DOI：
10.1080/00102202.2011.652788
复制
发表时间：
2012-05
影响因子：
1.9
通讯作者：
K. T. Kim;S. Hochgreb
中科院分区：
文献类型：
--
作者：
K. T. Kim;S. Hochgreb
为了了解甲烷/空气火焰传播到非均质反应物化学计量比时的燃烧-声相互作用，采用分层旋流稳定燃烧室对火焰描述函数（FDF）的振幅依赖性进行了详细的实验研究。采用相位同步OH平面激光诱导荧光（OH PLIF）技术研究了受迫火焰的局部反应区结构。为了确定振幅和频率依赖的强迫火焰响应，同时测量的入口速度和热释放速率振荡，使用恒温风速计和光电倍增管与窄带OH*/CH* 干涉滤波器。测量是在广泛的分层比率，包括内流富集（NH 2> NH3）和外流富集（NH3> NH3）的条件下进行的，并与空间和时间均匀情况下的基线条件（NH3 = NH3）进行比较。结果表明，对于所研究的入口条件，燃料分层对非受迫火焰和受迫火焰的局部和全局火焰结构有显著影响。在分层条件下，局部轮廓的长度尺度被发现是远远大于均匀的情况下，由于高的运动粘度与高温。当火焰受到高幅值声强迫时，层化效应对火焰-涡相互作用有显著影响，导致不同的FDF（幅值和扰动对流时间）演化模式响应于所施加的入口速度振荡的幅值。目前的实验研究表明，有意分层有可能消除或抑制有害的燃烧不稳定性问题的发生在贫预混气体涡轮机燃烧系统。
Detailed experimental investigations of the amplitude dependence of flame describing functions (FDF) were performed using a stratified swirl-stabilized combustor, in order to understand the combustion–acoustic interactions of CH4/air flames propagating into nonhomogeneous reactant stoichiometry. Phase-synchronized OH planar laser induced fluorescence (OH PLIF) measurements were used to investigate local reaction zone structures of forced flames. To determine the amplitude- and frequency-dependent forced flame response, simultaneous measurements of inlet velocity and heat release rate oscillations were made using a constant temperature anemometer and photomultiplier tubes with narrow-band OH*/CH* interference filters. The measurements were made over a wide range of stratification ratios, including inner stream enrichment (ϕ i > ϕ o ) and outer stream enrichment (ϕ o > ϕ i ) conditions, and compared to the baseline condition of spatially and temporally homogeneous cases (ϕ i = ϕ o ). Results show that for the inlet conditions investigated, fuel stratification has a significant influence on local and global flame structures of unforced and forced flames. Under stratified conditions, length scales of local contours were found to be much larger than the homogeneous case due to high kinematic viscosities associated with high temperature. Stratification has a remarkable effect on flame–vortex interactions when the flame is subjected to high-amplitude acoustic forcing, leading to different evolution patterns of FDF (amplitude and disturbance convective time) in response to the amplitude of the imposed inlet velocity oscillation. The present experimental investigation reveals that intentional stratification has the potential to eliminate or suppress the occurrence of detrimental combustion instability problems in lean-premixed gas turbine combustion systems.