Effects of hydrogen on the thermo-acoustics coupling mechanisms of low-swirl injector flames in a model gas turbine combustor

Experimental Study of Hydrogen Addition Effects on a Swirl-Stabilized Methane-Air Flame

“…Studies focused on the flame structures and combustion oscillations showed that the use of H 2 significantly altered the flame characteristics due to the different properties of transport and chemical reactivity [18,19]. Some investigations with a swirl-stabilized configuration indicated that the thermoacoustic instabilities were very sensitive to the H 2 molar fraction in the fuel blends [20,21].…”

Thermoacoustic combustion instability of propane‐oxy‐combustion with CO2dilution: Experimental analysis

“…The sound pressure and heat release fluctuation spectra obtained for the CO 2 -diluted, propane oxyfuel flames are presented in Figure 10 and Figure 11, respectively. 62,63 Consequently, the reduction in acoustic amplitude with the increase in H 2 concentration observed here can be attributable to the weakened flamevortex interaction as the amount of H 2 increases in the fuel. In the sound pressure spectrum (Figure 10), it can be observed that the amplitude of the 465 Hz oscillations drops from 0.0036 AU at 0% H 2 to about 0.0006 AU at 40% H 2 concentration.…”

Experimental Characterization of Response of Lean Premixed Low-Swirl Flames to Acoustic Excitations

“…However, it was considered that qualitative information on large scale heat release fluctuations can be derived from these images. Global heat release fluctuations of premixed hydrocarbon flames are commonly measured from chemiluminescence of CH* [21,22,25,26,39,41] or OH* [24,25,33,39,41]. Spatial distribution of heat release can be obtained from narrowband filtered chemiluminescence [24,26,39] or more accurately by laser-induced fluorescence methods like OH-PLIF [25,30,32,35,39].…”

“…Visible radiation is also employed in Refs. [21,23,33] and [37] to observe large scale flame dynamics during an acoustic cycle. Therefore, qualitative information obtained from visible emissions of lean premixed flames in this study should be helpful to illustrate large-scale oscillations of heat release.…”

“…Huang and Ratner [32] observed similar thermoacoustic coupling in the shear layer in local Rayleigh index maps for Strouhal numbers on the order of unity. Recent studies [33,34] on self-excited combustion instability of lowswirl flames in a model gas turbine combustor cite flame folding by vortices in the shear layer as a key driving mechanism of combustion instability.…”