CFD simulation of particle segregation in a rotating drum. Part I: Eulerian solid phase kinetic viscosity

Although the Eulerian approach coupling the kinetic theory of granular flow is usually used to study granular flows with relative lower solid fractions, it can be used to study relative denser granular flows if appropriate solid phase kinetic viscosity values were adopted. A granular bed surface fitting (BSF) method is proposed to determine the appropriate solid phase kinetic viscosities of the granular flows in a rotating drum. The specularity coefficient is also used to address the interaction between particles and the drum wall. The BSF solid phase kinetic viscosity increases with decreasing of particle sizes and drum rotational speeds. The BSF solid phase kinetic viscosity and the specularity coefficient follow a power-law relationship with 0.6–1.1 as the exponent of the specularity coefficient. The BSF solid phase kinetic viscosities for the particles of two different sizes are used to study particle segregation in a rotating drum. The core thickening segregation mechanism and the segregation band formations are well predicted.