First results of the delayed fluorescence velocimetry as applied to diesel spray diagnostics

M. Megahed; P. Roosen

doi:10.1117/12.150492

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6 August 1993 First results of the delayed fluorescence velocimetry as applied to diesel spray diagnostics

M. Megahed; P. Roosen

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Proceedings Volume 2052, Fifth International Conference on Laser Anemometry: Advances and Applications; (1993) https://doi.org/10.1117/12.150492
Event: Laser Anemometry: Advances and Applications: Fifth International Conference, 1993, Koningshof, Veldhoven, Netherlands

Abstract

One of the main parameters governing diesel spray formation is the fuel's velocity just beneath the nozzle. The high density of the injected liquid within the first few millimeters under the injector prohibits accurate measurements of this velocity. The liquid's velocity in this region has been mainly measured using intrusive methods and has been numerically calculated without considering the complex flow fields in the nozzle. A new optical method based on laser induced delayed fluorescence allowing the measurement of the fuel's velocity close to the nozzle is reported. The results are accurate to about 14% and represent the velocities of heavy oils within the first 2 - 5 mm beneath the nozzle. The development of the velocity over the injection period showed a drastic deceleration of the fuel within the first 3 mm beneath the nozzle. This is assumed to be due to the complex interaction of cavitation in the injection hole and pressure waves in the injection system which causes the start of atomization in the nozzle hole.

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M. Megahed and P. Roosen "First results of the delayed fluorescence velocimetry as applied to diesel spray diagnostics", Proc. SPIE 2052, Fifth International Conference on Laser Anemometry: Advances and Applications, (6 August 1993); https://doi.org/10.1117/12.150492

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