Influence of shaft distance on backflow performance of the lifting pump under stopping

• Published in: Journal of the Brazilian Society of Mechanical Sciences and Engineering Vol. 47; no. 9
• Main Authors: Wu, Xianfang, Zhu, Xinyue, Tan, Minggao, Hua, Runan, Liu, Houlin
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.09.2025; Springer Nature B.V
• Subjects: Computational fluid dynamics; Deep sea mining; Discrete element method; Engineering; Guide vanes; Hoisting; Liquid phases; Mechanical Engineering; Mining industry; Occupational safety; Particle collisions; Technical Paper; Two phase flow; Backflow; Lifting pump; Shaft distance; Pump shutdown; CFD-DEM coupling
• ISSN: 1678-5878; 1806-3691
• DOI: 10.1007/s40430-025-05713-8

Backflow during an emergency stop in a deep-sea lifting pump has a significant impact on mining safety as it may lead to particle blockage and cause the entire mining system to malfunction. The shaft distance between pump stages is a crucial parameter of the lifting pump; researching its structural influence is not only of great significance for improving pump backflow performance but also providing a theoretical basis for the design of high-performance deep-sea mining lifting pumps. Accordingly, a two-stage solid–liquid two-phase flow pump was selected as the subject of this study, with the coupling method of CFD-DEM (computational fluid dynamics–discrete element method) employed to numerically simulate particle backflow in the pump with shaft distances of 35 mm, 50 mm, and 65 mm, and the effect of shaft distance between pump stages on backflow performance was investigated. The results demonstrate that increasing the shaft distance contributes to a gradual reduction in the particle accumulation area in the first-stage pump, along with an increase in the liquid-phase backflow velocity and less particle backflow blockage in the first-stage pump. As the shaft distance between pump stages increases, the total number of particle collisions and particle quantity in the first-stage guide vane decrease, while the average particle backflow velocity and passing rate increase. When the shaft distance between pump stages was raised from 35 to 65 mm, the average particle backflow velocity and passing rate rose by 26.5% and 3.66%, respectively, indicating that the longer the shaft distance between pump stages, the better the backflow performance.