Modeling the pilot injection and the ignition process of a dual fuel injector with experimental data from a combustion chamber using detailed reaction kinetics
The introduction of the so called Emission Controlled Areas within the IMO Tier III legislation forces manufacturers of maritime propulsion systems to adherence to stringent emission thresholds. Dual fuel combustion, which is characterised by the injection of a small amount of fuel oil to ignite a premixed natural gas air mixture, constitutes an option to meet this target. High diesel substitution rates, resulting in very short pilot injections, oblige the injector into the ballistic working regime. This influences spray penetration, mixture formation and ignition behaviour. In the present work, a seven-hole dual fuel injector was measured in a combustion chamber to provide data for the generation of a CFD model using the commercial code AVL FIRE. The liquid and the vapour phase of the fuel spray were quantified by Mie-scattering and Schlieren-imaging technique for different chamber conditions.