Microscopic Characterization of Diesel Sprays at VCO Nozzle Exit 982542
A long-distance microscope with pulse-laser as optical shutter up to 25kHz was used to magnify the diesel spray at the nozzle hole vicinity onto 35-mm photographic film through a still or a high-speed drum camera. The injectors examined are high-pressure valve-covered-orifice (VCO) nozzles, from unit injector and common rail injection systems. For comparison, a mini-sac injector from a hydraulic unit injector is also investigated. A phase-Doppler particle analyzer (PDPA) system with an external digital clock was also used to measure the droplet size, velocity and time of arrival relative to the start of the injection event. The visualization results provide very interesting and dynamic information on spray structure, showing spray angle variations, primary breakup processes, and spray asymmetry not observed using conventional macroscopic visualization techniques. The near-field spray behavior is shown to strongly depend on the nozzle geometry, needle lift dynamics, and injection pressure, which is a function of the injection system.
Citation: Lai, M., Wang, T., Xie, X., Han, J. et al., "Microscopic Characterization of Diesel Sprays at VCO Nozzle Exit," SAE Technical Paper 982542, 1998, https://doi.org/10.4271/982542. Download Citation
Author(s):
Ming-Chia Lai, T.-C. Thomas Wang, Xingbin Xie, Jong-Sub Han, Naeim Henein, Ernest Schwarz, Walter Bryzik
Affiliated:
Mechanical Engineering Department, Wayne State University, U.S. Army TARDEC
Pages: 11
Event:
International Fall Fuels and Lubricants Meeting and Exposition
ISSN:
0148-7191
e-ISSN:
2688-3627
Also in:
SAE 1998 Transactions - Journal of Fuels and Lubricants-V107-4
Related Topics:
Nozzles
Imaging and visualization
Particulate matter (PM)
Optics
Pressure
Starters and starting
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