The effects of particle density and interstitial fluid viscosity on the dynamic properties of granular slurries in a rotating drum

• The increase of the fluid viscosity causes an increase in the angle of repose.
• The mean velocity will decrease with the increase of the fluid viscosity.
• The average granular temperature will decrease with increasing fluid viscosity.
• The diffusion coefficient increases with increasing particle density.

Experiments were performed to measure the dynamic properties of granular matter in a slurry rotating drum. Five different fluid viscosities, including air and four different liquid viscosities with mixtures of water and glycerin, as well as three different particle densities were used in the experiments. In this study, the purpose was to quantify the effects of the particle density and fluid drag force in a granular system.Particle tracking velocimetry was employed to measure the dynamic properties. Both the velocity of particle and granular temperature were obtained by averaging the experimental data. The angle of repose and diffusion coefficient were also calculated. The results show that the granular dynamic properties are strongly affected by the operational parameters. The mean velocity, obtained by averaging the velocities of all particles will decrease with an increase of the fluid viscosity. The average granular temperature will also decrease with increasing fluid viscosity. Moreover, the dimensionless number related to the dynamic properties is also discussed in the present study.

The dimensionless number G′, combined with the influence of the fluid viscosity, the acceleration of gravity, particle density and fluid density, are all used in this work. An increase of the dimensionless number G′ would cause the dimensionless dynamic angle of repose increase, and the dimensionless mean velocity, the dimensionless granular temperature and the dimensionless self-diffusion coefficient to decrease.Figure optionsDownload as PowerPoint slide