抄録
In 2002 the European Commission adopted a European Union strategy to reduce atmospheric emissions from seagoing ships. The strategy reports on the magnitude and impact of ship emissions in the EU, and sets out a number of actions to reduce the contribution of shipping to health and climate change. One possible approach for the reduction of NO_x and soot emissions of marine diesel engines is the use of multiple injection strategies, similar to the ones used in automotive diesel engines. In this way, diesel combustion could be optimized with respect to pollutant emissions, without compromising fuel efficiency. Our interest is in investigating the potential for emissions reduction and overall optimization of combustion in large two-stroke marine diesel engines, using numerical simulation. In this context, we study the effects of advanced injection strategies by utilizing Computational Fluid Dynamics (CFD) tools. We use the KIVA-3 code as the modeling platform, with improved models for spray breakup, autoignition and combustion. Here, we report first results, corresponding to pilot injections, which are visualized for the fuel injection and combustion processes, and are also mapped on temperature - equivalence ratio charts (T φ maps). This analysis reveals important information on pollutant formation mechanisms in large marine diesel engines, and suggests that fuel savings with simultaneous reduction of soot emissions may be feasible.
