Investigation of diesel spray characteristics from injectors with asymmetric hole distribution

Diesel spray profoundly influences combustion quality, engine performance, and exhaust gas emissions. Previous studies have primarily focused on understanding diesel spray characteristics and their impact on combustion, often using multi-hole injectors with one hole of interest. However, these studies overlook a crucial factor: the inherent asymmetry in diesel injector internal geometry, a result of manufacturing limitations acknowledged by industry experts. This study investigates the relationship between nozzle internal geometry asymmetry and diesel spray characteristics to clarify the dynamics of spray variation. X-ray computerized tomography is employed to measure nozzle internal geometry, while synchrotron X-ray technology enables high-speed visualization and phase-contrast imaging of diesel sprays with double exposure, facilitating local velocity measurement. Backlight imaging is employed to spray tip penetration and spray spreading angle. The analysis explores correlations between nozzle geometry and spray characteristics. Results indicate that the asymmetric hole distribution of diesel injectors significantly impacts hole-to-hole spray characteristics, particularly due to variations in the ratio of hole length to diameter.