Simultaneous Measurement Technique for Droplet Size and Velocity and its Application to Liquid Blob Breakup Process of Pre-Swirl Spray 18ICES/072
Authors
Jeekeun Lee - Chonbuk National University
Keiya Nishida - University of Hiroshima Byoungjoon Rho - Chonbuk National University
Kyukeun Song - Chonbuk National University
Abstract
The breakup and atomization processes of the pre-swirl spray, which is formed before the hollow-cone spray from a high-pressure swirl-type D.I. gasoline injector, were investigated experimentally. A microscopic imaging technique was applied to get the spatially high-resolution LIF tomograms of the pre-swirl spray. The droplet size and the individual droplets velocity were obtained by applying the imaging processing and the particle tracking techniques, respectively. The breakup regime of the pre-swirl spray includes the following four stages in the order of changes: (a) liquid column stage (SOI-0.13 ms); (b) liquid blob stage (0.13-0.4 ms); (c) ligament stage (0.4-0.6 ms); and (d) large-sized droplet stage (0.6 ms-after). The stages (a), (b) and (c) belong to the primary breakup process, and the stage (d) belongs to the secondary breakup process. The SMD of the pre-swirl spray during the breakup of the liquid blob is very large with a wide scatter, and then it steeply decreases during the breakup processes of the long-ligaments and the small-sized liquid blobs. In addition, during the breakup process of the large-sized droplets (0.6-0.8 ms from SOI), the SMD steeply decreases with time from SOI, and it shows larger value at 0.1 MPa than at 0.4 MPa.