CFD Simulation of Diesel Injection and Combustion

A Diesel spray and combustion model has been connected to the CFD-code StarCD. The paper provides an overview of the submodels implemented, which account for liquid core atomization, droplet secondary break-up, droplet collision, impingement, turbulent dispersion and evaporation. Auto-ignition and combustion is described by the Representative Interactive Flamelet (RIF)-model. This concept allows to separate the fluid dynamics from the chemical processes with their significantly smaller timescales, and enables to account for a sufficiently large number of chemical species and reactions in order to predict pollutant formation such as NOx and soot. The CFD-predictions are extensively compared to experimental data. Spray model validation cases focus on the distribution of droplet sizes, velocities and fuel vapor in free and impinging sprays. The combustion modeling predictions are compared to measurements of ignition delay times and the temporal and spatial development of the temperature and soot distribution within the spray.