Numerical and experimental investigations of new nozzle concepts for diesel injectors

摘要

The impact of diameter and shape changes of diesel injector nozzles on the internal flow and spray behavior is numerically investigated and compared to the experimental data obtained with new nozzle designs. The diameter was varied between 70 and 130 μm and the number of nozzle holes increased from 8 to 14. Furthermore, new nozzle hole concepts were investigated which feature different diameters in one hole circle (6 + 6 hole nozzle). A diameter ratio of 1.3 and of 2 was applied. The reduction in the spray hole diameter led to a reduction in the mass flow of the nozzle and to a diminished spray penetration. Using the 6 + 6 hole nozzle with a ratio of 1.3, very similar penetration depths were seen for both injection holes despite the different diameter. An increase of the diameter ratio or a design change of the smaller nozzles leads to the desired effect that the spray of the smaller nozzles shows significant smaller penetration depths than the one of the bigger holes.