Eccentric Needle Motion Effect on Spray Dynamics of Multi-hole Diesel Nozzle

The needle eccentricity has been found to be able to influence the in-nozzle flow characteristics and fuel sprays in the near-nozzle region. However, very few investigations have been conducted to unveil its inherent mechanism. In this study, the effect of needle eccentricity on the hole-to-hole variation is numerically studied using a simplified sac nozzle geometry with three fixed needle positions. The results showed that the effect of needle eccentricity on the hole-to-hole variation is dependent on the sac volume, and only when the sac volume is relatively small, the needle eccentricity can lead to an effective hole-to-hole variation.