Numerical Investigation of Spray Formation in Coaxial Nozzles

Kurzfassung

In this paper the results of numerical investigation of atomization process of liquid fuel (Diesel) in Laval and coaxial nozzles are presented. The calculations have been performed using CFD codes of STAR-CD. The dependences between the different cases of pressure drop and spray formation have been analysed. For that purpose a model to simulate unsteady two-phase atomization process has been employed. Results of transient flow through various 3D nozzle shapes and the resulting spray development have to be discussed. The three type of nozzle (Laval, converging and coaxial) are considered. It was found that for the nozzles under consideration the finer atomization occurs for low initial mass flow rates. The atomization process in such nozzles occurs by fragmentation between high velocity gas jet and fuel volume. Further, the pressure conditions of gas flow are of great relevance for atomization process.