Transport properties in sheared granular flows

This paper tends to review the experiments performed in a shear cell device at National Central University. The influences of wall conditions and particle solid fractions were investigated. The glass spheres with a mean diameter of 3 mm were used as granular materials. Three bi-directional stress gages were installed to measure the normal and shear stresses along the upper wall. The image processing technology and particle tracking method were employed to measure the average and fluctuation velocities in the streamwise and the transverse directions. By tracking the movements of particles continually, the variation in the mean-square diffusive displacements with time was plotted and the self-diffusion coefficient was determined. The self-diffusion coefficients in the streamwise direction were much higher than those in the transverse direction. Besides the fundamental observations in a shear device, this paper will briefly describe the technology of "moving granular bed filter" developed at National Central University. This technology is mainly developed for high temperature gas cleanup.