TWO-DIMENSIONAL DROPLET SIZE AND VOLUME FRACTION DISTRIBUTIONS FROM THE NEAR-INJECTOR REGION OF HIGH-PRESSURE DIESEL SPRAYS

Abstract

Droplet diameter and volume fraction measurements are reported as a function of radial and axial position near the injector orifice within a high-pressure spray typical of diesel systems. Injection system parameters were peak pressures of ~ 80 MPa and a single orifice injector with a 0.16 mm diameter and an L/D ratio of ~ 4. Two cases are presented and discussed in detail; injection into room ambient conditions and injection with combustion (initial conditions: 873 K, 12.5 atm). Scattered light at two infrared wavelengths was collected from a spatially resolved probe volume and, through scattering theory, both Sauter mean diameter and liquid volume fraction were produced. Spray properties were determined as a function of time at a number of points, and these points form a grid based on multiple axial and radial positions within the spray. Results from multiple, yet identical, events were used to construct twodimensional contour plots of the Sauter mean diameter and volume fraction within the spray.