CFD Analysis of a Model Combustor Ignition and Comparison with Experimental Results

Abstract

The ignition in a Micro Combustor, tested at the test facility M3 at DLR Lampoldshausen is modeled by the Eddy Dissipation Model (EDM). In order to avoid the EDM-typical over-prediction of the reaction rate in the wall boundary layers (flame “creeping” along walls), the reaction is disabled within 3 mm distance of the walls. Also, the reaction is disabled for temperatures of 400 K or lower, in order to reduce inaccuracies of burning velocities and possible flash backs. The SST turbulence model according to Menter (a blending of the k −ε and the k −ω model with automatic choice of linear/logarithmic near wall profiles) is applied for the analysis of the pre-ignition cold flow as well as for the ignition. A hexahedron mesh on a 1° segment of the supply domes, the injector, the combustor and a small ambient exit area is used. Finally, the numerical results are compared with experimental results.