Abstract
The relation between the surface kinetic angle of powdered particles and their shapes was studied by using two kinds of measuring apparatus: The one in which a base plate was fixed horizontally and the other in which a barrel turned slowly around a horizontal axis. The experimental results obtained from both methods indicated that the geometrical piling configulations of the powdered particles were controlled by the law of sliding friction until the pile angle with a horizontal plane reached to 30°.
Based on the Helz's theory of elasticity and the laws of solid friction, the surface kinetic angle was expressed theoretically by the following equation:
μr=tanφr=K(π/6·d3Ψ)-1/3α.r2/3
in which a new concept of a shape factor of powdered particles named‘degree of ratio to sphere’ was introduced. The calculated values from the above equation coincided fairly with the experimental values.
