Session: 04-29 Emissions hydrogen/ammonia II

Paper Number: 128817

128817 - Interplay Between Unburned Emissions and NOx Emissions From a Dual Swirl Hydrogen Air Injector 

The combination of OH-PLIF and PIV is employed to ana- lyze the structure of hydrogen/air flames stabilized by a double swirled injection system under globally lean and atmospheric conditions. The scrutinized flames exhibit two distinct reaction branches. The first, located in the central recirculation zone, is a diffusion-controlled reaction layer characterized by a relatively large thickness associated with low strain rates. The second branch, stabilized in the shear layer of the swirling jet, displays a structure strongly influenced by large coherent structures. Depending on operational conditions, this front may adopt either the form of a fully diffusive strained reaction layer anchored to the hydrogen injector lip or a lifted diffusion front with a leading-edge flame evolving into a partially premixed flame at high air injection velocities. Flue gas analysis reveals low NOx emission levels, typically below 10 ppm at 15% O2, for sufficiently large air injection velocities. The injector broad operational range is constrained only by the ultra-lean blowout limit reached for global equivalence ratios below 0.02. Furthermore, the injector demonstrates remarkable resilience to large and rapid perturba- tions in fuel flowrate. However, combustion efficiency tends to decline close to the lean blowout limit due to an increased oc- currence of fragmentations in the reaction layer, as evidenced by OH fluorescence images.

Presenting Author: Hervé Magnes Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France

Presenting Author Biography: - Currently PhD student on the combustion of hydrogen at IMFT-CNRS, TOULOUSE, France. The
main research topics are hydrogen flame stabilization, NOx emission and ignition process on
HYLON injector.
- Engineering degree from ISAE-ENSMA, POITIERS, FRANCE.

Authors:

Hervé Magnes Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France
Martin Vilespy Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France
Laurent Selle Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France
Thierry Poinsot Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France
Thierry Schuller Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France