Characterization Of Granular Materials Research Articles

Flowability of granular materials with industrial applications - An experimental approach

Designing bulk material handling equipment requires a thorough understanding of the mechanical behaviour of powders and grains. Experimental characterization of granular materials is introduced focusing on flowability. A new prototype is presented which performs granular column collapse tests. The device consists of a channel whose design accounts for test inspection using visualization techniques and load measurements. A reservoir is attached where packing state of the granular material can be adjusted before run-off to simulate actual handling conditions by fluidisation and deaeration of the pile. Bulk materials on the market, with a wide range of particle sizes, can be tested with the prototype and the results used for classification in terms of flowability to improve industrial equipment selection processes.

Characterization of Granular Materials with Internal Pores for Hydraulic Calculations Involving Fixed and Fluidized Beds

This study focuses on the characterization of porous granular materials for applications in hydraulics of fixed and fluidized beds. Different density measurement procedures were tested using five different sieved fractions of each of zeolite, activated carbon, and anthracite coal media to compare these procedures and to ascertain the effect of the density measurement method used on the calculation of other particle and bed properties. The mentioned particle and bed properties are the following: (i) particle density, (ii) particle size (equivalent diameter), (iii) sphericity, (iv) fixed-bed porosity, and (v) expanded-bed porosity during fluidization. The density of each of the 15 fractions was determined using four different methods: (i) cone test (ASTM C128-12), (ii) Le Châtelier flask method, (iii) soaking and straining, and (iv) skeletal density. The first three of these measure “wet density” (i.e., pores filled with liquid), the difference between them being in how the particles are saturated with liqu...

Development of a Cylindrical Probe Designed for Thermal Characterization of Granular Materials

This article describes a new thermophysical characterization method for granular materials. It is based on the creation of a cylindrical probe, fitted with peripheral flux and temperature sensors. These sensors record changes in thermal variables in the case of cylindrically symmetrical heat diffusion. A numerical exchange model integrated into an inversion algorithm identifies the thermal effusivity and diffusivity of the material being tested and the sensor/material contact resistance. In this first study, the method was applied to dry sand.

Micro-Macro Characterization of Granular Materials

The intrinsic complexity of granular materials stems from the fact that the characterizing variables at the micro-scale and the macro-scale are of different nature. Macroscopically, tensorial variables (stress tensor, strain tensor, fabric tensor) are commonly used based on Representative Volume Element (RVE), while vectorial variables (contact force, contact displacement, contact normal) are adopted at particle-scale. This paper mainly discusses some basic characterizations for these two scales, as well as their correlations. Numerical simulations using Discrete Element Method (DEM) are then conducted to show the evolutions of both microscopic and macroscopic variables during monotonic loading. It is indicated that the particle reorientations in the dense sample are much more pronounced than that in the loose one during shearing.