Numerical Simulation on Optimization of Diesel Nozzle

The changing of detailed structure of diesel nozzle tip greatly affect the flow characteristics in the nozzle hole and the performance of the following breakup of spray.This paper conducts three-dimensional numerical simulation for the cavitation flow fully developed in three types of nozzles,they are the standard(STD),the valve closed orifice(VCO) and the improved nozzle(IMPROVED) of the vertical multi-hole injector under different needle lifts with mixing multi-phase cavitation flow model.The study showed that the IMPROVED nozzle has better spray characteristics at low injection velocity,and the general performance of IMPROVED nozzle is better than that of the STD nozzle and the VCO nozzle.