Experimental and LES investigation of ignition of a spinning combustion technology combustor under relevant operating conditions

SAFRAN Helicopter Engines has developed the spinning combustion technology in which the burnt gases from one injector travel tangentially along the combustor annulus towards the neighboring injectors. Compared to a conventional design, this arrangement modifies the ignition process, which is a critical phase for aeroengines. In order to understand the ignition process in this technology, experiments and Large-Eddy Simulation (LES) have been performed in a cylindrical combustion chamber where the flow is injected tangentially (named Radius chamber). Three cases are considered with different strain and turbulence levels representative of real combustor flows. Micro calorimetry and the Background-Oriented Schlieren technique allows for detailed temporal measurements of energy deposited in the flame kernel. Pressure measurement and Schlieren imaging are used to study the flame propagation.  LES are performed with a 19-species and 184-reactions analytically-reduced chemistry together with the thickened flame approach allowing the description of the first instants of ignition in a quasi-DNS mode and ensuing flame propagation. Both a static and dynamic formulations of the wrinkling factor to describe sub-grid scale chemistry-turbulence interaction are used. Results show that LES is able to capture the flame kernel formation and trajectory as well as the time to reach maximum pressure within an error of 10% when using a dynamic formulation. On the other hand, the static formulation of the wrinkling factor predicts the time for maximum pressure within a maximum error of 20%.