High-speed microjet particles measurement using in-line pulsed holography

Abstract

Transient in-line holographic imaging system is optimized for recording the holograms of detonation loaded microjet particles with a velocity higher than 5 km/s. Then an adaptive multithreshold image segmentation method is developed to improve the measurement precision of particle size and number. The measured size of ejected particles is from several microns to over ten microns, and the processing errors of particle number and size are less than 5% and 15%, respectively. The statistical results also show that the size, number, and velocity of microjet particles vary depending on the surface conditions of the Al metal debris. Compared with a uniform metal sample, the nonuniform metal sample with cone-shaped hole exhibits more ejected particles, larger particle size, and higher velocity.