Design of High-Speed Shadowgraphy System for Sizing and Velocimetry of Particles

In this paper, design and production of a high power pulsating illuminator for particles imaging in shadowgraph technique is presented. Based on high contrast of shadowgraph images and no need for high power illuminator, commercial light emitted diode (LED) is used as an alternative for laser light. The designed pulsating high power light source works with minimum pulse width of 125 ns, frequency of 500 Hz, and maximum electrical current of about 15 A. A trigger compatible with camera and light source is designed for synchronizing light pulses and camera shutter. In addition, commercial DSLR camera was used for implementation of single frame-multi pulse technique with no need for high speed camera. The images recorded by a DSLR camera shows drops with velocity of about 20-30 m/s and size of about 100-200 um being captured.