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ICLASS 94<br>Proceedings of the Sixth International Conference on Liquid Atomization and Spray Systems

ISBN:
978-1-56700-019-1 (Print)
978-1-56700-445-5 (Online)

APPLICATION OF IMAGE PROCESSING METHOD FOR ANALYSIS OF LIQUID JET DISINTEGRATION PROCESS

Norihiko Iki
AIST, Japan

K. Endoh
Tohoku University Sendai, Japan

T. Inamura
Department of Aeronautics and Space Engineering, Tohoku University, Sendai, Japan

Nobuki Nagai
Department of Aeronautics and Space Engineering, Tohoku University, Aramaki Aza Aoba, Aoba-ku, Sendai, Japan

Abstract

The disintegration process of the liquid jet injected perpendicularly into a high speed air stream is investigated. Surface wave speed, diameter and droplet velocities are measured from video images produced by double pulsed photography. The images are examined and processed for evidence of atomization mechanisms and desirable data. Two stroboscopes with different color filters backlighted the liquid jet for double flash photography. Color images of liquid disintegration process are recorded on the color frame memory by a color CCD camera. Differences of each color image indicate motions of surface waves and droplets during the time interval between the flashes. Cross correlation coefficients of the images are used to calculate these differences. The images are processed by a profitable filter to obtain desirable data. An edge detect filter was used for measurement of liquid surface wave velocity. The results show surface wave velocities measured by image processing are lower than those measured by the twin laser beam attenuation technique. The image processing method has a larger measurement volume than the laser beam measurement method and the difference causes the velocity defect between two methods. For measurement of droplet velocity, a threshold filter gave acceptable data compared to the data of LDV. However, small and fast droplets might be eliminated from the measurements because of limitation of image resolution and light source.