The Influence of Diesel Nozzle Structure on Internal Flow Characteristics

摘要

Based on X-ray CT scan technology in Shanghai Synchrotron Radiation Facility (SSRF), the inner structure of a side jet single-hole nozzle was obtained and its parameters around the inlet circle were measured. Further researches were carried out with the flow rate test bench about the influences of structure parameters symmetry on the internal flow characteristics and cavitation. Results showed that: the size deviation of inlet diameter, outlet diameter and nozzle length around the inlet circle are relatively small, while the inlet rounding radius is obviously distributed unevenly. Because of that, the cavitation had already showed up when the injection pressure was 40 MPa and the critical cavitation number equalled to 1.032, which should not take place according to the traditional theory. Thus, when relative studies are carried out, it is important for researches to take fully consideration of the size deviation of nozzle structure parameters, especially for the inlet rounding radius, to achieve more reliable conclusions.