JMEE HomeIssue Contents

A Head Loss and Limit Deposit Velocity Framework
S. A. Miedema and R. C. Ramsdell

Many models for slurry transport exist. Usually the models describe one of the 5 main flow regimes: fixed or stationary bed transport; sliding bed transport; heterogeneous transport; homogeneous transport and sliding flow transport. The transition between these flow regimes is seldom described, as well as the difference between spatial and delivered concentration and the behavior of graded sands or gravels. A framework is described connecting the different flow regimes. Additional models for; the limit deposit velocity, the holdup function, the bed height, the concentration distribution and graded sands and gravels, complete the framework. The framework is based on constant spatial volumetric concentration curves for uniform sands and gravels. The models for the flow regimes and the limit deposit velocity are based on energy considerations. By means of a holdup function, the constant spatial volumetric concentration curves can be transformed into constant delivered volumetric concentration curves. Curves for graded sands and gravels can be constructed by splitting the particle size distribution (PSD) into fractions and use the superposition principle on the resulting curves of each fraction.

The framework is validated with many experiments from literature.

Keywords: Slurry Transport, Hydraulic Gradient, Limit Deposit Velocity

Full Text (IP)