Numerical Investigation on Hydraulic Conveying of Fine Slag Particles Based on a Coupled Modelling

Abstract

Hydraulic conveying is a core technology for fine slag transportation due to its continuity characteristics. However, research on hydraulic conveying of micro-sized particles with varying sizes remains limited, thereby constraining the optimization design of the transport system. This study employs a coupled Computational Fluid Dynamics-Discrete Element Method (CFD-DEM) model to simulate the hydraulic conveying process of micro-sized particles in pipelines. We systematically examine the influence of transport velocity, particle concentration, particle density, and pipe inclination angle on the characteristics of the two-phase flow. The findings predict that optimal particle suspension is achieved at a transport velocity of 3-4 m/s, whereas excessive velocity (>5 m/s) induces particle clustering, resulting in an increase in pressure drop; the particle concentration exceeding 7.4% generates slug flow, severely impacting transport efficiency; increasing particle density intensifies the deposition, and the pressure drop rises. Furthermore, the pressure drop is predicted to reach a maximum at a pipe inclination of 60°, and horizontal pipes exhibit the highest particle axial velocity. This study elucidates the flow regime transition patterns and energy consumption characteristics in the hydraulic conveying, providing essential insights for the optimization design of related transport systems.