the angle of repose of soil particles is an important factor for determining critical shear stress for initiation of soil particles motion during the erosion process. there are different methods for measuring the angle of particle repose and the result of each method is somewhat different from those of the others. sliding and fixed-base piling methods are the two most common methods in the lite...

the friction properties of granular materials play an important role in the determination of specifications for designing hoppers, transporting passages, dryers, silos and machines through which grain flows. in this study, the angle of repose and internal friction coefficient were determined for three common wheat varieties (sardary, gaspard and saysoter) at four moisture contents (12, 15, 18, ...

Aiming at predicting what happens in reality inside mills, the contact parameters of iron ore particles for discrete element method (DEM) simulations should be determined accurately. To allow the irregular shape to be accurately determined, the sphere clump method was employed in modelling the particle shape. The inter-particle contact parameters were systematically altered whilst the contact p...

According to USP 30-NF 25 [1], powder flow with repose angles between 25–30° powder flow is excellent, among 31–35° the flow is good and within 36–40° the flow is fair. For values higher than 41°, the powder has bad flow properties. The best angle of repose was shown by powder obtained from tests 4 and 6 (33 ± 2° and 33 ± 1° in Table S1), whose flow can be considered good. Moreover, the powders...

We investigate the effect of nanoscale variations in the surface roughness of individual particles on macroscale granular flow characteristics. Experiments were conducted in circular rotating tumblers with smooth and rough 2 and 3 mm steel particles. The smooth beads had a rms surface roughness of approximately 30 to 60 nm; rough beads had a surface roughness of approximately 240 to 350 nm. The...

The discrete element method (DEM) has been used as a popular simulation method in order to verify the designs by visualizing how materials flow through complex equipment geometries.  Although DEM simulation is a powerful design tool, finding a DEM model that includes all real material properties is not computationally feasible.  In order to obtain more realistic results, particle energy loss du...

The mixing dynamics of granular materials immersed in a liquid was experimentally studied in a quasi-2D rotating drum. A DV (SONY DCR-TRV900 NTSC) motion corder analyzer was used to record the motions of granular materials. The effects of interstitial fluid viscosity and filling degree on the mixing index, mixing rate constant, and dynamic repose angle in the rotating drum were investigated and...

The current research focuses on the estimation of bulk density and angle of repose of tea leaves at different moisture content and size and development of a mathematical model for bulk density and angle of repose using response surface methodology followed by numerical optimization of responses using desirability functions. Further work was done on the design optimization of feed hopper and met...

We report the results of three dimensional molecular dynamic simulations on the angle of repose of a sandpile formed by pouring mono-sized cohesionless spherical grains into a granular Hele-Shaw cell. In particular, we are interested to investigate the effects of those variables which may impact significantly on pattern formation of granular mixtures in Hele-Shaw cells. The results indicate tha...