Flame Imaging of Gas-Turbine Relight

摘要

High-altitude relight inside a lean-direct-injection gas-turbine combustor is investigated experimentally by high-nspeed imaging.Realistic operating conditions are simulated in a ground-based test facility, with two conditions beingnstudied: one inside and one outside the combustor ignition loop. The motion of hot gases during the early stages ofnrelight is recorded using a high-speed camera. An algorithmis developed to track the flamemovement and breakup,nrevealing important characteristics of the flame development process, including stabilization timescales, spatialntrajectories, and typical velocities of hot gas motion. Although the observed patterns of ignition failure are in broadnagreement with results from laboratory-scale studies, other aspects of relight behavior are not reproduced innlaboratory experiments employing simplified flow geometries and operating conditions. For example, when thenspark discharge occurs, the air velocity below the igniter in a real combustor is much less strongly correlated tonignition outcome than laboratory studies would suggest. Nevertheless, later flame development and stabilization arenlargely controlled by the cold flowfield, implying that the location of the igniter may, in the first instance, be selectednbased on the combustor cold flow.