ID 329

X-Ray Measurements of Fuel Spray Specific Surface Area and Sauter Mean Diameter for Cavitating and Non-Cavitating Diesel Sprays

 

Abstract:

Specific surface area measurements of diesel sprays were performed using ultra-small-angle x-ray scattering at the 9-ID beamline of the Advanced Photon Source at Argonne National Laboratory. Injector orifice type, rail pressure, and ambient pressure effects were explored. The targeted sprays belonged to three different single-hole nozzles fitted with duplicate light-duty common rail diesel injector bodies. One of the orifices has been designed to cavitate under typical diesel operating pressure conditions, while the other two orifices are its non-cavitating analogs with nominally identical geometries. Measurements were conducted in the near-nozzle region along the spray axis as well as across the width of the jet. These data provide information with regard to not only the rate of shear-driven atomization but also the radial dispersion of the fuel droplets at each of the measured conditions. In addition, when coupled with complementary measurements of the projected density, these data quantify the Sauter mean diameter of the fuel droplets. Both the specific surface area and Sauter mean diameter measurements can be used to educate spray breakup models that rely on droplet information in the near-nozzle region, where optical diagnostics have proven challenging.