Abstract
Estimation method for the stresses exerting on a powder in a silo under centrifugal force was developed, and Jenike's model which predicts major stress on an arch of powder was modified in order to apply it to the arch under centrifugal force. Based on the model together with the unconfined yield strength of powder, a new method was proposed to estimate the span of critical arch.
Visualization of flow patterns of a kaolin powder under the centrifugal force of about 150g to 1000g was carried out using a miniature silo (diameter: 40mm, apex angle of cone: 60°, and outlet diameter: 3 to 16mm). Experimental results were in good agreement with those estimated by the present method when the outlet diameter gave an intermediate flow pattern between a funnel flow and an arch formation or a rat hole.
