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 two-dimensional contour plots of the Sauter mean diameter and volume fraction within the spray.