ABSTRACT:

Some recent efforts for better understanding and prediction of upward pipe flow of Newtonian solid-liquid slurries are discussed. Experimental data are presented for slip velocity of 10 mm particles in a 150 mm pipe and for hydraulic gradient of coarse sand in a 20 mm vertical pipe. Proposed correlations are suitable for practical applications.

INTRODUCTION

Vertical hydraulic pipeline transportation is the most promising technique for deep-sea mining systems of nodules and has many other industrial applications. However the physical mechanism of solid liquid mixture flows in a vertical pipeline is different than in a horizontal pipeline. In upward now of large and heavy solid particles their velocity diners from the water velocity and the available slip velocity is an important feature of the now. The prediction of turbulent flow headloss for such mixtures has remained one of the most difficult theoretical and practical problems. Recent interest in the field has produced several relatively new approaches to the problem. The objective of this paper is to review these approaches for a Newtonian hydromixture, to utilize some slip velocity measurements in Poland and Ukraine and develop a prognostic model of hydraulic losses, as well as to pay attention to the practical requirement of a design model of hydraulic losses.

VERTICAL SLURRY FLOW REGIMES

The high-velocity regime (Um > Nw) is a steady flow with a practically uniform distribution of the solids C along the height of the pipe. As a result the hydraulic gradient of the flow is constant and have a specific form. From a hydraulic point of view the flow can be treated as a flow of homogeneous Newtonian fluid with higher than the carrier liquid density and viscosity depending on the concentration, size and shape of the solids.

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