Browsing by Author "Gatt, FC"

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    Flow of spheres and near spheres in cylindrical vessels, Part II - pebble transit in recirculated random packings.
    (Australian Atomic Energy Commission, 1970-06) Gatt, FC
    An experimental and statistical investigation has been made of the transit of individual pebbles in recirculated random packings of equal spherical pebbles. Slightly aspherical pebbles were also studied Pebbles of 1.00 inch or 0.75 inch nominal diameter were used to form 30 inch deep beds in a 30 inch diameter vessel with a concave base in the form of a cone with 25 degree slope, the pebbles flowed downwards under the influence of gravity. The independent variables whose effects were studied were the radial position of the pebble, the number of pebbles in the bed situated beneath the seeding position, the pebble size and sphericity, and the amount of recirculation. Both transient and equilibrium conditions were considered. An estimate was made of the mean amount of recirculation required to reach equilibrium from an initially random packing. For spherical pebbles this was approximately 1.6 times the number of pebbles in the bed, and for aspherical pebbles it was 2,8 times the number, formulae are given for predicting the amount of recirculation required for a particular pebble to emerge from the bed.
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    Flow of spheres and near spheres in cylindrical vessels, Part IV - individual flow paths in recirculated random packings.
    (Australian Atomic Energy Commission, 1973-12) Gatt, FC
    An experimental investigation was made of the transit of individual pebbles in recirculated random packings of equal spherical or aspherical pebbles. Pebbles of 1.0 inch or 0.75 inch nominal diameter and 3.0 or 3.4 specific gravity are used to form beds in a 30 inch diameter vessel with a concave base and single axial outlet. The pebbles flow downwards under the influence of gravity through a rotating extractor in the base. A radio-actively tagged pebble is inserted at the top of the bed and as it descends with the pebble packing its position is detected and recorded at intervals using a tracking device. In this way tracks and velocities of pebbles seeded in the bed for various combinations of seeding radius, bed and pebble parameters are determined, and are found to be generally of 'streamline' form. The extractor rotation has very little effect on the motion of the pebbles in the bed. Using the tracks of tagged pebbles, patterns and effects of flow zones are deduced. Transit numbers of tagged pebbles are found to be in good agreement with the results of similar experiments recorded in Part III of this report series.
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    Flow of spheres and near-spheres in cylindrical vessels, Part III - transit spectra for recirculated random packings.
    (Australian Atomic Energy Commission, 1972-03) Gatt, FC
    The work presented is an experimental and statistical investigation of the transit number spectra (a particular transport characteristic) of identical pebbles in recirculated random packings in a cylindrical vessel with a base and a single central (axial) outlet. The packings form beds which flow downwards under the influence of gravity through an extractor in the vessel's base. The experimental variables studied are the base angle, the pebble seeding radius, the pebble size, shape and specific gravity, the packing height, the vessel base shape and the vertical position of the vessel's extractor. The purpose of the work was partly to study these variables for their effect on the amount of recirculation required for a particular pebble to emerge from the vessel and partly to obtain statistics on individual beds.