The complex circumstances of deep-sea mining result in unexpected accidents. When a pump abruptly stops working during mining in deep seas, several tons of minerals need to be refluxed. The commonly used computational fluid dynamics (CFD) method cannot simulate the required reflux because the volume of particles is neglected. However, this parameter can be calculated using Discrete Element Method-computational fluid dynamics (DEM-CFD). Using this method, the movement of particles and the location of the blockage becomes evident. In this study, DEM-CFD was used to simulate the reflux of nodules of diameter d ≤ 10, d ≤ 20, and d ≤ 50 mm with a volume concentration of 8%. The results indicated that particles of diameter d ≤ 50 mm cannot be refluxed and they are likely to accumulate at the junction of the impeller and vanes. Thus, the diameter of the particles needs to be controlled for effective functioning of the lifting pumps, and prevent deep-sea mining accidents.

Metal minerals in deep sea are considered to be the most important mineral resources in the 21st century. With the development of science and technology, deep-sea mining has gained more and more attention, and the pipeline lifting method is the most promising for mining. It is particularly important to use the pump as a key component in the pipeline upgrading. In this paper, the DEM–CFD method is used to study the solid–liquid two-phase fluid flow in the Deep-Sea lifting motor pump. Data about the distribution of pressure on the suction surface and pressure surface as well as the distribution of particles in the pump under different rotation speed can be obtained. Tests verify the efficiency and head of the pump by numerical simulation. It provides a theoretical method for the study of solid–liquid two-phase fluid flow in deep-sea mining.

Owing to the scarcity of terrestrial mineral resources, deep-sea mining has gradually become a popular topic of research. As a feasible solution for deep-sea mining, pipeline transportation has become increasingly important. Here, the CFD–DEM framework is used to study the flow law of particles of different sizes in deep-sea mining pipelines. The numerical results, which were verified by experiments, indicated that the particle size must be less than 1/3rd of the diameter of the mining pipeline.

Through discrete element method-computational fluid dynamics, the internal flow field and particle motion law of a two-stage deep-sea lifting pump at different rotational speeds were analyzed in this work. In addition, the physical phenomena, such as flow field velocity, secondary flow, and particle flow, were studied. The relationship between the rotational speed of the lifting pump and solid–liquid two-phase flow was investigated. An experiment on the hydraulic performance of the lift pump showed that the resulting lift and efficiency were consistent with the numerical simulation data. When the rotational speed was 1,450 rpm, the particles can obtain a higher kinetic energy from the flow field, the flow was more stable, and particle deposition was reduced.

To predict the vibrational conditions, the generation mechanism, and action law of pressure pulsation and radial force, a computational fluid dynamics (CFD) study of a deep‐sea electric lifting pump operating under different off‐design conditions was performed. The time‐domain and frequency‐domain response of the pressure pulsation at different monitoring points and the radial force of impeller distribution were obtained. Differences in pressure pulsation characteristics between the first stage and second stage were observed. The variation law and influential factors of the radial force under different flow rates were discussed. The present investigation shows that the flow field caused by rotor‐stator interaction is not uniform, resulting in uneven pressure distribution and pressure pulsation, the combined effects of which produce fluctuating radial forces. Parameters obtained via simulations including head, efficiency, and power, which can reflect the hydraulic performance of the pump, agree well with experimental results; thus, the accuracy of the simulation model and the calculation method was verified. This study provides a basis for improving the structure and reliability of an electric lifting pump.