Abstract
Coefficients of wall friction were measured for salt powder against various wall materials, by using a press-loading shear tester developed. Two ring-plates of cold-press stainless steel and polyvinyl chloride were prepared for the tests. The effect of moisture content on the coefficient was also examined.
The following results were obtained:
Coefficients of wall friction against stainless steel and poly-vinyl chloride were found to be 0.25 and 0.38 respectively. In those tests against stainless steel, the coefficient obtained was independent on moisture content except the test for the original salt. The coefficient for the original salt was 30% smaller than that for the other moisture salts in the lower stress region. The effect of the coefficient on the flowability of salt powder was discussed by using a model of bulk flow of salt in a vertical pipe.It was found that the vertica stress of powder in the bulk was subject to a greater influence ofthe coefficient as the depth from the upper surface of the bulk increased.
