気固分散系における粉体のレオロジー評価

Abstract

Design of particle handling processes requires the characteristics of powder on flowability. Although various indices exist, most were obtained from the static characteristics and cannot express the dynamic effect. In the case of liquid or gas, the characteristic of flowability is represented by viscosity. Especially in the case of liquid-solid suspension, it is well known that the viscosity changes by the degree of particle agglomeration, and the agglomeration of suspended particles is determined by “particle interaction”. However, the characteristics of powder layer have not been well understood. In this study, a method to measure the viscosity of a gas-solid suspension was developed. FT4 powder rheometer was used to measure the torque exerting on the blade, which rotated and descended into a powder layer. These data were used to calculate the viscosity of powder layer. We concluded that the well-known powder index for flowability may represent its dynamic characteristics and that the powder viscosity may provide more detailed information on powder flowability.