DESIGN VELOCITIES FOR HYDRAULIC CONVEYING OF SETTLING SUSPENSIONS

Probably the greatest unresolved problem in designing large hydraulic transport lines for settling suspensions lies in the selection of a conveying velocity. Too low a velocity results in settling-out of the solids and possible blockage; too high a velocity results in wasteful use of power, high rates of wear in pumps and pipeline, and degradation of the solids. Some designers have a breadth of experience which they can use when designing lines for materials not too dissimilar from those they have encountered before but their experience is not available to everyone. What is available is an overwhelming mass of different correlations with no reliable method of choosing between them. Each of the correlations may be satisfactory for the limited range of conditions on which it is based, but when applied to large-scale pipelines these correlations are often found to overpredict the power requirements considerably. Very often the only solution is to carry out an expensive full-scale trial. In this paper, a critical review is made of 55 correlations for predicting design velocity which have been found in the literature. It is not the primary aim of the paper to submit yet another correlation but to analyze the effect of the principal variables. It is shown that none of the correlations is entirely satisfactory, mainly because of the difficulty in defining the properties of the solid particles and their interaction with the fluid. Thus in the second half of this paper it is suggested that a better approach is to use a scale-up procedure in which the effects of the particle properties are measured directly on a small scale. It is suggested that future research should be directed towards finding scale-up rules and some possible forms are suggested.

  • Supplemental Notes:
    • Presented at HYDROTRANSPORT 3--Third International Conference on the Hydraulic Transport of Solids in Pipes, Colorado School of Mines, Golden, Colo., May 15-17, 1974. Sponsored by BHRA Fluid Engineering. Complete set of Conference papers available for $45.00.
  • Corporate Authors:

    Colorado School of Mines

    1500 Illinois Street
    Golden, CO  USA  80401
  • Authors:
    • Carleton, A J
    • Cheng, DCH
  • Publication Date: 1974-5

Media Info

  • Pagination: 17 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00056467
  • Record Type: Publication
  • Source Agency: British Hydrodynamics Research Association
  • Report/Paper Numbers: Paper E5
  • Files: TRIS
  • Created Date: Jul 15 1974 12:00AM