3DCFD-Modeling of a Hydrogen Combustion-Process with Regard to Simulation Stability and Emissions

In the context of the energy transition, CO₂-neutral solutions are of enormous importance for all sectors, but especially for the mobility sector. Hydrogen as an energy carrier has therefore been the focus of research and development for some time. However, the development of hydrogen combustion engines is in many respects still in the conception phase. Automotive system providers and engineering companies in the field of software development and simulation are showing great interest in the topic. In a joint project with the industrial partners Robert Bosch GmbH and AVL Germany, combustion in a H₂-DI-engine for use in light-duty vehicles was methodically investigated using the CFD tool AVL FIRE®. The collaboration between Robert Bosch GmbH and the Institute for Mobile Systems (IMS) at Otto von Guericke University Magdeburg has produced a model study in which model approaches for the combustion of hydrogen can be analyzed. Plausibility checks and a validation of the models with measurement data were carried out for the resulting models. The major advantage of a hydrogen combustion engine is its potential CO₂ neutrality. However, with the goal of climate neutrality and compliance with criteria pollutant emission legislation, an investigation of exhaust emissions was necessary. Due to the very high temperatures during the combustion, in locally rich areas within the combustion chamber nitrogen oxides (NO_x) are produced. The formation process of NO_x in the H₂-Air mixture was therefore investigated and modelled by simulation. A further aim is to provide the necessary data for a variation of the operating point in order to be able to achieve a more precise NO_x prediction with simulation models.