Green Electrical Control of Combustion

• Applicant: Professor Dr.-Ing. Christian Oliver Paschereit, since 2/2022
• Subject Area: Fluid Mechanics
• Term: from 2017 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 391398589

Combustion instabilities constitute a severe challenge in the development of efficient low-emission combustion systems, such as gas turbines for aeronautical and power generation applications. Previous work has shown the principle capability of nanosecond repetitively pulsed (NRP) plasma discharges to mitigate this undesirable unsteady combustion phenomenon in academic configurations; however, essential physical effects associated with the application of this technology in real gas turbine engines for aircraft propulsion and power generation have not been considered yet. These effects are related to 1.) liquid-fueled spray flames, 2.) elevated operating pressure, and 3.) high-frequency non-planar modes. The GECCO project will tackle these three aspects with dedicated experiments and high-fidelity simulations. A common swirl-burner platform will be used for all three aspects to maximize synergy effects between the individual work packages. The AVBP code, well established for turbulent combustion simulations of academic and industrial configurations, will be combined with a plasma code to account for the effects of NRP plasma discharges on turbulent flames, taking into account ultrafast heating as well as slower thermal and chemical effects. Once validated on the basis of experimental data, this numerical tool will be essential in achieving a comprehensive understanding of the plasma-flame-acoustic interaction related to the 3 effects mentioned above. The effect of NRP discharges on the dynamics of spray flames will be assessed in detailed measurements (phase-Doppler anemometry, light-sheet tomography, particle image velocimetry), investigating the influence on the cold spray, the flame shape, and the dynamic response to acoustic perturbations (flame transfer function, FTF). To assess and demonstrate the potential of NRP discharges in the mitigation of high-frequency azimuthal instabilities, the swirl burner will be equipped with circumferentially distributed plasma actuation. The response of the flame to this type of forcing will be experimentally assessed using azimuthally resolved measurements (pressure, chemiluminescence). Plasma-flame-acoustic interaction at elevated pressures will be investigated in a high-pressure facility. The effect of NRP on the FTF and the response of the flame to low-frequency modulated harmonic plasma forcing will be measured up to 10 bar. All experimental tasks are accompanied by corresponding simulations that will provide a more detailed understanding of the interaction mechanisms than accessible by measurements only. In the final part of the project, NRP discharge forcing will be utilized to control acoustically coupled combustion oscillations in the three experimental facilities (spray flames, high-frequency modes, elevated pressure). GECCO may, thus, increase the fundamental understanding of dynamic plasma-flame interaction and, on the other hand, bring this technology significantly closer to real applications.

• DFG Programme: Research Grants
• International Connection: France, Saudi Arabia
• Cooperation Partners: Professorin Dr. Bénédicte Cuenot; Professorin Dr. Deanna Lacoste; Professor Dr. Thierry Schuller
• Ehemaliger Antragsteller: Professor Dr.-Ing. Jonas Moeck, until 2/2022