Experimental and Modeling Study of Sand Transport in Slightly Upward Inclined Solid-Liquid Flow

Solid transport in inclined pipes is widely encountered in industrial operations, such as oil and gas production and mining. Understanding the mechanism of solid transport in inclined flow lines has significant importance for the development of these practical applications as well as productivity and safety issues. This paper presents an experimental investigation on the hydraulic transport of solid particles in pipelines in a 5° upward inclined orientation. The pipe had an internal diameter of 2-inch (50.8 mm). Water-solid flows which comprised sand (25–600 μm) and water were tested at solids concentrations between 0.01%–0.5% volume-to-volume ratio (v/v). The tests were carried out by observing the movement of the sand particles in a transparent pipe while regulating the flow rate of the fluid. The critical transport velocity (V_C) was determined using video recordings. V_C was observed to increase with an increase in sand concentration and sand particle diameter. The critical velocities obtained are compared with results obtained from previous experimental work in inclined and horizontal flow and existing modeling approaches available in the literature.