Comparison of wall friction measurements by Jenike shear tester and ring shear tester

For a silo design, it is very important to understand the friction characteristics of bulk solids with silo walls. This so-called wall friction angles were measured in this study with two different testers: Jenike shear tester and Schulze ring shear tester (RST). Soft PE plastic pellets A was used as the tested bulk solids while stainless steel SS 304 and aluminum Al 6061were selected as wall plates. It was found that the most important parameter in this study is wall roughness. With decreasing wall roughness, wall friction angles decrease no matter which tester was used. Wall friction angles for both testers were similar if wall roughness was similar. The only exception is under the testing condition of the low pressure (500 Pa) on a wall plate. In addition, the impact of testing temperatures (22 and 37 °C) has been described in this study. © 2011 Hosokawa Powder Technology Foundation.