High Speed Schlieren by Using High Power Light Emitting Diodes

This paper describes the details of a novel high-speed schlieren imaging setup. In addition to the very precise layout in the schlieren setup, it is necessary to freeze the phenomenon in order to have a high resolution in the temperature contours. For high-speed imaging, a high-power diode has been used in over-current conditions. LED is a novel light source that have many advantages over lasers. By reducing the duty cycle, it is possible to increase the power of every pulses. Eventually, high quality images can be captured by synchronization of camera and the light source. Some factors including the effect of high speed imaging, setting the precise location of knife, and capturing low temperature gradient were investigated to have a high resolution and high quality schlieren setup. The results show that schlieren setup has an acceptable accuracy in detecting low temperature gradients and can be used to study the flame features.