Bowen's method for the scale-up of pilot plant data relating hydraulic gradient with volumentric flowrate for various pipe diameters to large scale pipelines is investigated. Pilot plant data for 0.0531 M (2 in.) diameter pipelines in the turbulent regime for two cement slurries are used to predict hydraulic gradients for pipelines up to 0.3289 M (13 in.) diameter. Good agreement is obtained between the predicted hydraulic gradients and a limited amount of experimental data for the 0.3289 M (13 in.) diameter pipeline. Owing to scatter in the small-scale data it is necessary to estimate the degree of uncertainty in the predicted hydraulic gradients for the full-scale pipeline by extending Bowen's method of calculate the 90% confidence bands for the hydraulic gradient vs volumentric flowrate relationship for both the small-scale and full-scale pipelines. These confidence bands give the outside limits within which 90% of the predicted hydraulic gradients will fall and the best-fit line shows the most probably predicted value. This approach is particularly important when scaling up a factor of 8 on diameter and by a factor of about 100 on volumetric flowrate as an average band width of 10% on either side of the best-fit line for the small-scale data becomes about 65% below and 170% above the best-fit line for the large-scale clay slurry pipeline. The significance of the confidence band is that calculations of hydraulic gradient based on the best-fit value could give an underestimate up to 63%. Equally well a significant overestimate could occur. However, increasing underestimation or overestimation is associated with decreasing probability of occurrence. Despite these limitations, Bowen's method is more reliable in principle than alternative ones because it uses small-scale turbulent data to scale up in the turbulent regime. Much of the scatter in the pilot plant is thought to be due to degration of the slurry during pumping so that improved scale-up will be achieved by modifying the pumping rig to reduce degradation which should greatly improve its accuracy. (Author) /TRRL/

  • Corporate Authors:

    British Hydromechanics Research Association

    Cranfield MK43 0AJ, Bedfordshire,   England 
  • Authors:
    • Kenchington, J M
  • Publication Date: 1973

Media Info

  • Features: Figures; References; Tables;

Subject/Index Terms

Filing Info

  • Accession Number: 00132628
  • Record Type: Publication
  • Source Agency: Transport and Road Research Laboratory (TRRL)
  • Report/Paper Numbers: Analytic
  • Files: ITRD, TRIS
  • Created Date: Nov 9 1977 12:00AM