Light emitting diode applied to fast-speed schlieren device

Schlieren device is an important method for the measurement of transient flow field. The illumination effect serves as a vital role for its measuring result. A lighting system based on light emitting diode (LED) was designed to solve the problem of schlieren's illumination. The structure and etendue of schlieren device was analyzed, and the light flux of the object plane was calculated. According to the calculated result, the type of LED was selected, the layout and the optical collimating system were designed. The model of the lighting system was built through Tracepro, the illuminance distribution and light flux were analyzed. The calculated result indicated the lighting system based on LED met the challenge of schlieren device.