Browsing by Author "Tingate, GA"

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    Some geometrical properties of packing of equal spheres in cylindrical vessels, Part V - adaption of model to packings in cylindrical vessels
    (Australian Atomic Energy Commission, 1973-05) Tingate, GA
    Following the exploratory study reported in Part I, detailed experimental determinations have been made of the properties of a range of unbiased random packings with cylinder-to-sphere diameter ratios of 11.4 and 8.71. Properties at the dense end of the range depend on the diameter ratio. Properties at the loose end of the range are independent of the diameter ratio, and agree closely with those computed from the model developed in Part IV for the semi-infinite case. The model is adapted to the cylindrical case by means of quadratic equations whose coefficients depend on the cylinder-to-sphere diameter ratio. Although the adapted model is based on experiments with comparatively small diameter ratios, it is shown to hold for larger ratios, without the need to call further on experimentally determined properties. It is shown that commonly used preparation methods, such as placing or pouring spheres on the top surface, can result in packings with radial bias. Two methods of preparing unbiased random packings are described.
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    Some geometrical properties of packings of equal spheres in cylindrical vessels, Part I - exploratory study of random packings in small vessels
    (Australian Atomic Energy Commission, 1970-04) Tingate, GA
    An experimental method is described for determining some of the mean geometrical properties of packings of equal spheres in cylindrical vessels, essentially it involves determining the volumes of the sphere material in an outer region of thickness one sphere diameter, and the remaining central region. Related properties, including the mean void fractions of the two regions, can then be calculated. Since the properties of the central region of random packings prepared by a particular method are almost independent of the cylinder-to-sphere diameter ratio it was possible to conduct exploratory experiments using small cylinders. The packings were prepared by a variety of methods. General expressions are given for calculating related properties from the observations, and also for extending the results to larger vessels to an estimated accuracy of about ± 2 percent. The accuracy of about ± 1 percent inherent in the method may be achieved by refinements such as the use of vessels of larger diameter and the elimination of end effects.
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    Some geometrical properties of packings of equal spheres in cylindrical vessels, Part III - basic model away from the influence of wall effects
    (Australian Atomic Energy Commission, 1970-01) Ridgway, NW; Tingate, GA
    An experimental study of the structure of random packings of equal spheres in cylindrical vessels, which indicated the existence of a continuous range, has been followed by an analytical investigation. A model was developed on the basis that random packings, away from the influence of wall effects, can form by a process of expansion from the densest possible packing. Equations are derived connecting the mean void fraction, the mean number of points of contact, and other related properties. Both the three-dimensional and the two-dimensional cases are considered, and are found to have similar features. The equations give values which are in good agreement with available experimental results and with values computed by other means.
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    Some geometrical properties of packings of equal spheres in cylindrical vessels, Part IV - extension of model to outer region of semi-infinite vessel with plane wall.
    (Australian Atomic Energy Commission, 1971-10) Tingate, GA
    A range of random packings has been prepared in a prismatic vessel with a plane vertical transparent wall, simulating a semi-infinite vessel. Observations have been made in the outer region of the packings, using and extending the experimental method described in Part 1 of the series. The three-dimensional model presented in Part III has been extended to the outer region of unbiased packings in such a vessel. Equations from Part III are used, together with some of the properties of the regular arrays not previously considered. The rhombohedral and cubic arrays are shown to be members of a family of regular arrays, some of whose properties agree closely with experimentally determined properties of unbiased random packings over the range normally obtained in practice. The model is also shown to be in fair agreement with observed properties in the outer region of the loosest random packings prepared in the laboratory, enabling estimates to be made of some of their properties in the central region which have not so far been determined experimentally. The two-dimensional model presented in Part II is also extended to the outer region, and the computed results are supported by a limited experimental study.