Experimental study of hydraulic transport of large particles in horizontal pipes

Abstract

is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible. AbstractThis article presents an experimental study of the hydraulic transport of very large solid particles (above 5 mm) in an horizontal pipe. Two specific masses are used for the solids. The solids are spheres that are large with respect to the diameter of the pipe (5, 10 and 15%) or real stones of arbitrary shapes but constant specific mass and a size distribution similar to the tested spherical beads. Finally, mixtures of size and / or specific mass are studied. The regimes are characterized with differential pressure measurements and visualizations. The results are compared to empirical models based on dimensionless numbers, together with 1D models that are based on mass and momentum balance. A model for the transport of large particles in vertical pipes is also proposed and tested on data available in the Literature, in order to compare the trends that are observed in the present experiments in a horizontal pipe to the trends predicted for a vertical pipe. The results show that the grain size and specific mass have a strong effect on the transition point between regimes with a stationary bed and dispersed flows. The pressure drops are moreover smaller for large particles in the horizontal part contrary to what occurs for vertical pipes, and to the predictions of the empirical correlations.

What is the “active layer”?

“…A recent demonstration with direct relevance to bed load transport is given by Frey and Church [] (Figure ). Experiments with sand subject to shear by running water show that motion may extend to a depth of as much as 10 grain diameters below the surface while the bed surface remains reasonably well‐defined but, at sufficiently high flows, the bed load layer becomes a slurry with an ill‐defined surface that may be multiple grains deep [e.g., Ravelet et al ., ].…”

A head loss model for slurry transport in the heterogeneous regime

“…Until now papers of the following researchers have been used to analyze, verify and validate the new theory regarding the head loss curves: Blatch (1906), O'Brien andFolsom (1937), Soleil and Ballade (1952), Durand and Condolios (1952), Newitt et al (1955), Worster and Denny (1955), Gibert (1960), Fuhrboter (1961, Silin and Kobernik (1962), Thomas (1965), Zandi and Govatos (1967), Wiedenroth (1967), Fowkes and Wancheck (1969), Babcock (1970), Graf et al (1970), Yagi et al (1972), Karasik (1973), Kazanskij (1978Kazanskij ( , 1980, Boothroyde et al (1979), Clift et al (1982aClift et al ( , 1982b, Scheurel (1985), Doron et al (1987), Gillies (1993), Blythe and Czarnotta (1995), Doron and Barnea (1995), Matousek (1997), Schaan and Shook (2000), Matousek (2004), Gillies et al (2004), Whitlock et al (2004), Ni et al (2004Ni et al ( , 2008, Ming et al (2007), Vlasak (2008), Ravelet et al (2012), Vlasak et al (2012) and many more. Because of the enormous amount of data it is not possible to show everything, so a selection of graphs giving the essence of the verification and validation will be shown.…”

Ballast Flow Characteristics of Discharging Pipeline in Shield Slurry System

“…In Section 4, the influence law of ballast carrying performance is Many scholars conducted experiments and simulation studies on the particle motion in the pipeline system. Li-an et al [4], Van Wijk et al [5], Zouaoui et al [6], and Ravelet et al [7] established a pipeline circulation experiment system, with a tube diameter of 40-150 mm and extension distance of 5-25 m, and discussed the critical slip velocity of 5-85 mm spherical particle in the pipeline, the particle motion state, and the pressure loss characteristics. So far, no experimental platform has been formed to the shield slurry system, and the experimental results of the published studies have varied.…”