Development and application of an automatic measurement method for nozzle orifice diameter and length

摘要

Diesel sprays are important to engine combustion and emission formation processes, however, their behaviors are difficult to predict as they are very sensitive to the internal geometries of the nozzle. Based on synchrotron radiation x-ray tomography, a novel method is presented for measuring automatically the orifice diameter and length of fuel nozzles. According to this method, a clear definition of orifice inlet and outlet is given, and the diameters along the orifice from inlet to outlet as well as the orifice length can be measured. Measurements of a single-hole nozzle and an eight-hole nozzle have been performed accordingly. The results show that this method can automatically measure the orifice diameters from outlet to inlet along the whole orifice axis with relatively high precision, regardless of whether it is a single-hole or a multi-hole nozzle. The profile of the diameters obtained shows the differences between the nominal dimensions and the actual ones, which gives a more precise feedback for nozzle manufacture, and provides a new basis for precisely studying the impacts of internal geometries on spray behavior.