Effects of Hydrogen-Enrichment on Flame-Holding of Natural Gas Jet Flames in Crossflow at Elevated Temperature and Press
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Effects of Hydrogen‑Enrichment on Flame‑Holding of Natural Gas Jet Flames in Crossflow at Elevated Temperature and Pressure Pankaj Saini1 · Ianko Chterev1 · Jhon Pareja1 · Manfred Aigner1 · Isaac Boxx1 Received: 10 August 2020 / Accepted: 3 November 2020 © The Author(s) 2020
Abstract The effect of hydrogen ( H2 ) enrichment on the flame-holding characteristics of two natural gas jet flames in crossflow is investigated here, experimentally. The flame and flowfield measurements are analyzed using simultaneously acquired high-speed (10 kHz) stereoscopic particle image velocimetry, planar laser-induced fluorescence of the hydroxyl radical, and OH* chemiluminescence. The flames, enriched with 20% and 40% H2 , by volume, are studied at conditions typical of the mixing duct of a modern gas turbine engine; specifically in confinement, at 10 bars, and with a crossflow preheat of 530 K. Consistent with previous findings, the 40% H2 flame was found to be stabilized on the windward and leeward side of the jet, while the 20% H2 flame was stabilized only on the leeward side. Analysis of mean and instantaneous velocity fields showed no major differences in the trajectories and principal compressive strain fields of the two flames. The presence of the windward stabilized flame in the 40% H2 case was, however, found to decrease the centerline velocity decay and greatly reduce or eliminate large scale vortices along the windward shear layer. The difference in the flame-holding here was attributed to the difference in the extinction strain rate from the addition of hydrogen, which would impact the local and global extinction of the flame along the high shear windward region of the flame. Keywords Jet in crossflow · Hydrogen · Laser diagnostics · High pressure
1 Introduction With the increasing utilization of wind and solar energy for power generation, there is a growing interest in the use of hydrogen ( H2 ) as a means by which to store and recover energy generated during off-peak demand periods. One strategy for recovering energy stored as hydrogen is through its combustion in a gas turbine powerplant. As large scale gas turbine powerplants are now generally designed around the combustion of natural gas, which has significantly different combustion dynamics, it is more feasible to deliver * Isaac Boxx [email protected] 1
Institut für Verbrennungstechnik, Deutsches Zentrum für Luft- und Raumfahrt, Pfaffenwaldring 38‑40, Stuttgart, Germany
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Flow, Turbulence and Combustion
hydrogen to the combustor via admixture with natural gas than in its pure form. Despite this, the delivery of a hydrogen-enriched fuel to a combustor designed around pure natural gas poses significant technical challenges. Key among these is the possibility of a flashback event leading to the stabilization of a flame at or near the wall of the fuel-air premixing channel. Whereas a flashback event is certainly undesirable in gas turbine combustor, if it leads to flame-holding at or near the fuel-injector, the results can be catastrop
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