CFD-Based Investigation of Ice Slurry Pigging and Optimization of Cleaning Parameters
Ice slurry pigging is an emerging technology for cleaning water supply pipelines, yet quantitative understanding of its cleaning mechanisms and optimal operating conditions remains limited. This study developed a computational fluid dynamics (CFD) model integrating the kinetic theory of granular flows (KTGF), the Euler-Euler method, and the shear stress transport (SST) model to simulate ice slurry flow and wall shear stress distribution. The model was validated against experimental data, showing a 6.4% error in particle concentration distribution, a 3.3% average error in solid-phase velocity in the mainstream region, and a pressure drop error within 20%. A total of 125 simulations were performed under varying initial concentrations (20%–60%), particle diameters (0.3–1.0 mm), and flow velocities (0.2–1.0 m/s). Results indicate that higher initial concentrations (60%) achieve effective cleaning of both upper and lower pipe walls, with an effective shear stress ratio of 77.39%. Larger particles exhibit pronounced upward movement, increasing non-uniformity in solid distribution. Flow velocity is the dominant factor affecting wall shear stress; at 1.0 m/s, the effective shear stress ratio reaches 83.16%. The optimal parameters for cumulative shear stress were identified as 50% initial concentration, 0.5 mm particle diameter, and 1.0 m/s flow velocity, yielding an average cumulative shear stress of 11.59 Pa·s. For effective cumulative shear stress, the same parameters produced 9.89 Pa·s, while the highest effective shear stress ratio (88.50%) was achieved with 0.3 mm particles at 1.0 m/s and 50% concentration. This research provides theoretical guidance for ice slurry pigging operations in water supply pipelines.