Granular dynamics in vibrated beds

TY - THES

T1 - Granular dynamics in vibrated beds

AU - Zeilstra, Christiaan

PY - 2007/5/11

Y1 - 2007/5/11

N2 - Granular matter subject to vibration is found to display a wide range of interesting phenomena, and for this reason it has been a popular research topic in academia for decades. Depending on the particle properties and vibration parameters, the flow behavior of the material can be very different, behaving as a solid, liquid or even a gas, leading to a wealth of phenomena such as heaping, convection, pattern formation, etc. The processing of particle mixtures may even lead to segregation, which is often undesirable. To make matters more complex, additional forces such as those from the interstitial gas come into play when the particles are small, leading to new and sometimes very surprising phenomena. In the study of such complex systems, computer simulations can play an important role since they can provide data that is not accessible in experiments, and since interactions can be switched on and off at will it is relatively easy to study the effects of parameters separately. Moreover, preliminary simulations can provide a window of desired operating conditions that can be explored more fully in focused experiments. In this thesis, the flow and segregation behavior of granular matter subject to vertical vibrations is studied by numerical modeling and experimentation. As a second, separate subject, the dynamics of a large intruder particle when forced through a bed of much smaller particles is studied. The topics in order of appearance: (i) wall-induced granular convection, (ii) air-induced segregation of fine bronze and glass particles, (iii) solids circulation in gas-vibro fluidized beds, (iv) dynamics of a large sphere upon impact on a static granular bed, and (v) dynamics of a large sphere in a fluidized granular bed.

AB - Granular matter subject to vibration is found to display a wide range of interesting phenomena, and for this reason it has been a popular research topic in academia for decades. Depending on the particle properties and vibration parameters, the flow behavior of the material can be very different, behaving as a solid, liquid or even a gas, leading to a wealth of phenomena such as heaping, convection, pattern formation, etc. The processing of particle mixtures may even lead to segregation, which is often undesirable. To make matters more complex, additional forces such as those from the interstitial gas come into play when the particles are small, leading to new and sometimes very surprising phenomena. In the study of such complex systems, computer simulations can play an important role since they can provide data that is not accessible in experiments, and since interactions can be switched on and off at will it is relatively easy to study the effects of parameters separately. Moreover, preliminary simulations can provide a window of desired operating conditions that can be explored more fully in focused experiments. In this thesis, the flow and segregation behavior of granular matter subject to vertical vibrations is studied by numerical modeling and experimentation. As a second, separate subject, the dynamics of a large intruder particle when forced through a bed of much smaller particles is studied. The topics in order of appearance: (i) wall-induced granular convection, (ii) air-induced segregation of fine bronze and glass particles, (iii) solids circulation in gas-vibro fluidized beds, (iv) dynamics of a large sphere upon impact on a static granular bed, and (v) dynamics of a large sphere in a fluidized granular bed.

KW - IR-57836

M3 - PhD Thesis - Research UT, graduation UT

SN - 978-90-365-2486-5

PB - University of Twente

CY - Enschede

ER -