Parameters for Bed Slip Point in Two-Phase Flow

Abstract

Earlier work showed that the limit of deposition is given by the slip point, when the bed begins to slide. It had been found that the pressure gradient at slip point depends on the angle subtended by the bed and other factors. In this paper, suitable parameters representative of the pressure gradient, discharge and concentration of solids at the slip point are expressed in terms of this angle. For specific cases, with given pipe size and particle properties, the angle of deposition can be eliminated by plotting gradient parameter versus discharge parameter. This gives a graph similar to those generally used for plotting experimental results for two-phase pipeline flow, on which the locus of the slip point defines regions with and without deposition. It is found that the discharge at the slip point defines regions with and without deposition. It is found that the discharge at the slip point rises to a maximum and then decreases with increasing gradient. In combination with efficiency considerations, this indicates that it is desirable to operate pipelines with high solids' concentration.