Numerical Simulation of Unsteady Nozzle Flow and Spray Formation under Diesel Engine Conditions

In this paper a numerical approach for the prediction of the unsteady atomization process of liquid fuel in Diesel engine is presented. The dependences between the transient nozzle flow and spray formation are analysed. For that purpose models to simulate unsteady nozzle flows including the transient behaviour of cavitation and two-phase atomization process are employed. Results of transient flow through various 3D nozzle shapes (one- and multi-hole nozzle) and the resulting spray development are discussed. The flow predictions agree well with quantitative characteristics of nozzle flows and spray structures and with experimental results obtained for the case of the flow in a high speed diesel injector.