The Effect of Flow Pattern of Slurry Flow on Pressure Loss in Horizontal Pipes

Abstract

The purpose of this paper is to develop a reliable design tool for predicting the pressure loss based on a theoretical model in which the condition factor (a degree of homogeneity) represents flow patterns and is correlated with the geometric parameter of concentration distribution curves. By using the model the effect of the system’s variables and the properties of the solids on the Durand’s φ–φ plot, an obvious relationship between the head loss parameter and the modified Froude number, of computed pressure loss can be explained.

Verification and Application of Design Model for Settling Slurry Transport in Pipes

“…If the pressure drops of heterogeneous flow in pipes are analysed, the friction factor f between the solids and the pipe decreases with increasing velocity, as reported by Sato et al [5]. This fact shows that in heterogeneous flow, or intermediate regime between saltation and pseudo-homogeneous flows, some portions of the solids are assumed to be transported in saltation or sliding movement and others in suspension.…”

“…These flow patterns can be characterized by typical in-situ concentration profiles as shown in Figure 2. For a two dimensional steady and uniform flow in a horizontal pipe, the profile of solids can be represented by [5,7]:…”

“…Since most of the correlations were however derived at different flow regimes which depend on the mean velocity of the flow, the boundaries between the regimes should be determined whereas it is not easy to clearly distinguish one regime to another by observation. The objective of this paper is to demonstrate the applicability of an analytical model [5] to the settling slurry flow in horizontal pipes by using the Slurry Flow Database developed by Seitshiro et al [6] and to clarify the design procedure for the optimum operation condition. It is shown that both a condition factor indicating concentration profiles and a generalized particle Reynolds number are vital to predict the energy needed for transporting the slurry.…”