The Multi-Sized Slurry Flows in Horizontal Pipes : Innovated Models and Verification

Abstract

Although multi-sized particles slurries are transported in practical pipelines, most reported correlations were proposed for single-size slurries. If the average diameter of solids is used to estimate the drag coefficient of multi-sized particles slurries, the hydraulic gradients with these correlations lead to considerable scatter of data . Kazanskij , Moro , and STSJ (Slurry Transport Society of Japan) [4] summarised some empirical equations of hydraulic gradient of slurry flow with experimental data. The Wasp method [5] recommended by Liu [6] has been used by designers of pipeline systems for predicting hydraulic gradient of compound slurries of homogeneous and heterogeneous flows. However, the method is limited for application to a wide range of transport conditions. Kaushal et al. [7] also discussed the limitations and attempted to modify the method. They concluded that the Wasp method provided reasonable accurate results at limited low concentrations. The purpose of this paper is to discuss the limitations of application of other researchers' correlations and to develop innovated models, based on the single-size slurry model of Seitshiro et al. [8] The analytical models depend on particle size distribution: (1) coarse-coarse model; for a slurry consisting of two fine particles in high concentration. The fine solids are defined as particles with sizes smaller than the critical diameter [9] in this study. For both models, it is assumed that the coarse solids in the slurry do not hinder each other's movements. Experiments were performed in a 1-inch transparent pipe with sand-bakelite mixed slurries. The data of Shook et al. , Boothroyde et al. , and that of this study were used to verify the application of the models. The analytical results suggest that the innovated models can be effective for designing slurry pipelines.