| Mixing is one of the most important steps in handling powders in many industries e.g., the chemical, metallurgical, pharmaceutical, and food processing industries, because it strongly affects the composition of their main products. To mention only one important example in the pharmaceutical industry, mixing affects the potency of tablets such that if a problem of non homogeneity in its components results, it becomes a risk to human health.;To obtain an in depth understanding of mixing behavior, most previous studies have been emphasized in different systems such as rotating cylinders, tote blenders, v-blenders, double cone blenders, etc which are the most used nowadays in industries of solid handling. The progress has been substantial, however, because of the fact that most of the work has been done regarding only 2 dimensions, fundamental comprehension of the phenomena is still hidden. Real industrial applications require the understanding in three dimensions and only few studies along these lines has been done, for example, the use of new techniques such as positron emission particle tracking (PEPT) which is a noninvasive method that follows the motion of single radioactively labeled tracer particle to study their displacement in three axes. The use of MRI is another not so common technique in this field and the reason of the limitation of the use of these equipments is the high costs involved, and the complexity to have them in a common laboratory.;Considering the limitations and complications experienced in the general study of granular mixing, this work focused on developing a simple system consisting of a box with two moving walls and three static walls where the imposed shear strain was varied following a periodic function which permits to study the granular material's random movement and the mixing of the granular material.;The goal was to demonstrate experimentally, with a relatively simple system, the importance of taking into consideration the three dimensions and to obtain insights of the physical phenomena (compaction, dilation, interface slip, chaos, and segregation) involved in 3-dimensional granular flow. The system allows targeting specific phenomena, thus better understanding can be drawn from the experimental results.;The results are explained in three chapters. In the first, the effect of experiments at different imposed shear strains, wall displacements, time, and wall perturbation in the mixing on the surface of the cavity and in the z-axis were studied. Segregation was another phenomenon considered to understand the diverse responses of the mixing in the system when problems of non-homogeneity appear. In the second chapter the effects of different particle size distributions and dilation are shown. Finally, the third chapter concerns the effect of initial filling level in global mixing.;The study reveals that the best mixing is found near the moving walls and in the superficial layer. A triangular pattern with a height decrease that is associated with an increase in mixing was obtained at the bottom of the mixing chamber. The triangle size depended on the length of the mixing chamber, the velocity and wall displacement, the particle size, and the initial filling level. Mixing in the superficial layer follows a chaotic trend. The phenomenon of dilation was significant, playing an important role in the mixing performance varying the expansion of the bed linearly with the particle size. |
