Image-based measurement of particle movement in rotating cylinders

Rotary kilns are important thermal exchangers widely used in metallurgical and chemical processes. The heat transfer process of the kiln is determined mainly by the motion behavior of the particle inside the kiln. In this paper, an image-processing system is provided to study particle movement. It consists of a two-dimensional rotating cylinder, a video camera and a processing computer. The position of a tracer particle in each image is measured by using simple threshold segmentation algorithm. Results prove the effectiveness of the method. The downstream velocity profile of the particle is found to have a peak and its magnitude decreases with increasing distance to the bed surface.