A rheometer for measuring the properties of granular materials

A great many technological applications such as pneumatic handling of grains and minerals, drying of particles, gasification of solid fuels, require an understanding of the properties of granular solids. Material parameters which can describe the common phenomena exhibited by these granular materials, such as dilatancy, cohesion, adhesion, frictional resistance, etc. need to be incorporated in the model and methods devised for measuring and quantifying them. Reliable experiments are required to measure the properties of these materials. However, this branch of rheology has not been as well studied as the rheology of fluids due to the difficulties inherent to grannular materials in that they exhibit both solidlike and fluid-like properties. Here, we discuss the development of an instrument which can evaluate the material properties of grannular solids. Experimental investigations verify the commonly exhibited phenomena by these materials and estimate the various forces which are generated due to the flow of these materials, thereby enabling their characterization.