*With recent advancements in materials and heat transfer, power generating gas turbine operation is limited by emissions output. At low operating loads, carbon monoxide (CO) is the limiting emissions factor, while at base load, Nitric Oxide (NO~x~) is what drives gas turbine operation. A major influence in the emissions output of the combustor is the downstream reacting jet-in-crossflow. At low loads the reacting jet is run lean or with dilution air to mitigate CO; at base loads, more fuel is split to the axial jet to decrease residence time and mitigate thermal NO formation. Additionally, due to the high temperature of the fuel and air, they are mixed closed to injection point resulting in a partially premixed jet.*

*The current work studies the effects of partial premixing on a reacting jet-in-crossflow in a five atmosphere axially staged combustor at stationary gas turbine relevant conditions. Four different premixed levels are studied: fully premixed, non-premixed, and two intermediate partially premixed levels. Flow-field dynamics of the reacting jet-in-crossflow are analyzed using particle image velocimetry (PIV), and flame behavior is quantified by employing CH~2~O planar laser induced florescence (PLIF). NO and CO measurements are made at the exit of the facility using a Horiba emissions analyzer.*

*The axially staged combustion facility consists of a vitiator which provides hot exhaust products for the axial jet at temperatures (1350-1650°C) and flowrates relevant to gas turbines. The test section has three optical access windows for laser diagnostics and a top plate with a half inch wall flush injector with a coaxial air-fuel mixing method that is leveraged to change the premixed level. The facility is choked using a choke plate where an emissions probe is placed. The emission line is brought to an ice bath to prohibit further emission formation, and then to the emissions analyzer. The momentum flux ratio is held nominally constant at industry relevant conditions, and the experiments are run over a range of operating loads. Flame-flow field interaction is presented and reference to corresponding emissions levels.*

Keywords: Emissions, partial premixing, high pressure, axially staged combustion, reacting jet in crossflow, PIV, PLIF, NO~x~, CO


Partial Premixing Effects on the Reacting Jet of a High Pressure Axially Staged Combustor

Division / Sponsor:
International Gas Turbine Institute (IGTI)

Paper Proceedings: https://asmedigitalcollection.asme.org/GT/GT2020/volume/84058

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