The paper reports the recent results obtained on the applicability of cross-sectional digitaludimaging method to study particle flow characteristics in 3D particle beds forced to move byudgravity or shear. X-ray CT imaging technique is widely used in medical diagnostics and, duringudthe last decades, its spatial and temporal resolution has been improved significantly. In this study,udan attempt was made to use this technique for engineering purposes. Two experimental set-upsudwith different types of particle flows were investigated using Siemens Somatom Plus type CTudequipment. A series of trials were carried out in a small model hopper with flat bottom andudalmost cylindrical side wall slightly deviating from verticality. Non steady-state flow was studiedudduring the outflow of particulate material from this vessel, through a central hole at the bottom.udFurther investigation was fulfilled in a modified Cuette-type shearing device to study steady-stateudshear flow. This equipment consisted of an almost cylindrical vessel identical to that used forudgravity flow measurements, and a smaller inner cylinder rotating within this vessel concentrically,udaround its vertical axis. The surface of the inner cylinder was notched vertically, i.e.udperpendicularly to the direction of rotation to increase wall friction between the particles and theudcylinder. Almost spherical sucrose granules, also used for gravity flow measurements, were filledudinto the gap between the rotating cylinder and the outer wall of the equipment. Movement ofudparticles took place due to shear, generated within the particle bed. By using X-ray CT technique,udcross-sectional digital images were obtained in every two seconds for both types of particle flows.udFor this, the cross-sectional variation of the local Hounsfield density values were measured in audmatrix of 0.1x0.1x2.0 mm space elements. It was proved that the applied non-invasive crosssectionaludimaging technique was suitable to distinguish the stationary and moving particleudregions, and by this, to estimate the location of the boundary zone between them.
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