We developed a highspeed, multiparameter laser imaging system for the study of turbulent flames at the high pressure, high thermal load conditions found in a modern gas turbine combustor. This system consists of a dual-plane, laser-induced fluorescence system for the imaging of combustion radicals and fuel tracers, a stereoscopic particle image velocimetry system to acquire 3-component velocity measurements of combustor flow-fields, and a chemiluminescence imaging system. All three sub-systems can be operated simultaneously at high (10 kHz) acquisition rates over long (up to several seconds at a time) measurement periods.
We utilized this powerful new measurement system to study the effect of increasing hydrogen admixture and chamber pressure on the structure and dynamics of turbulent flames of natural gas, with a particular focus on questions of applied technical interest. Specifically, we used this measurement system to study the mechanisms responsible for lift-off and flame-holding of a series of jet-flames in crossflow issuing from a generic gas turbine fuel-injector at pressures of up to 15 bars, and with hydrogen fuel fractions of up to 100%. We acquired measurements to study the structure and dynamics of flames of hydrogen-enriched natural gas at conditions of extreme turbulent intensity (Re_t = 10,500) and at pressures of up to 7 bars in a piloted, premixed Bunsen burner. Finally, we acquired an unprecedented series of measurements of the structure and dynamics of partially-premixed swirl flames of hydrogen-enriched natural gas in a gas turbine model combustor at pressures of up to 5 bars, and thermal loads of up to 185kW. These measurements yielded extensive new insight into the effect of hydrogen on flame dynamics, combustion instabilities and flow-flame interaction. Analysis of the unique and extremely rich database of experimental measurements we acquired in this project has delivered new insight into how hydrogen affects the structure and dynamics of turbulent flames at the extreme conditions found in a gas turbine combustor.
To maximize both the scientific and technical impact of this project, we have shared experimental data from each test case extensively with numerical simulation and combustion modelling teams from around the world through collaborative research initiatives. These collaborations have generated new insight into the effect of hydrogen on combustor dynamics, flame-stabilization and thermoacoustic pulsation. The shared data sets have enabled researchers to test and improve the performance of their predictive analysis tools against high quality experimental data acquired in technically challenging test cases. Initial results of these collaborations have already been published in several peer-reviewed journals. Additional papers are currently in preparation or under review.
