LONG-WORKING-DISTANCE MICROSCOPE USED FOR DIESEL INJECTION SPRAY IMAGING

An optical system for analysis of diesel spray penetration and atomiza tion has been developed. The basic system is based on a microscope wit h a long working distance (230 mm) and a modest resolution. The magnif ication is variable between 1:1 and 50:1 on the camera plane. This ena bles the study of individual droplets with a diameter of 5 mu m. A num ber of different techniques have been used together with the basic sys tem to study different parts of the spray. They include the dark-groun d technique, double exposure, and ordinary magnification. The size, sp eed, and direction of propagation of the individual droplets have been calculated using the elongation of the droplet image caused by the du ration time of the flash. (C) 1996 Society of Photo-Optical Instrument ation Engineers.