The deep-sea mining lift pump is one of the pivotal components in deep-sea mineral transportation systems and its internal flow is very complex; consequently, unraveling its unsteady flow behavior pattern holds immense practical value. This study adopts numerical methods to analyze the time-averaged distribution characteristics of the internal flow field in mining lift pumps, as well as the flow field’s pulsation intensity distribution characteristics, the vortex’s spatiotemporal evolution process in both moving and static cascades, and the time- and frequency-domain pulsation characteristics of internal pressure in each flow passage component under four different flow conditions are also investigated. The hydraulic properties of mining lift pumps under these four different conditions are also evaluated, and the outcomes are benchmarked against those of numerical predictions. Our findings reveal that the interplay between impeller blades and guide vanes significantly influences the pump’s flow characteristics, with the pump’s unsteady flow influencing its hydraulic properties. Experimental validation of this system confirms that the pump under study is in line with design specifications in terms of hydraulic properties. The method validation test on the prototype pump shows that the SST k-ω model is capable of successfully forecasting instability in the flow features of deep-sea mining lift pumps. These results will serve as a theoretical reference for regulating the flow state inside deep-sea mining lift pumps.

It is essential to investigate the performance output and flow characteristics within deep-sea mineral extraction pumps using appropriate numerical calculation methods. In this study, by taking a deep-sea mineral extraction pump prototype as the subject, a small-scale mineral extraction pump model was constructed. Computational fluid dynamics methods, incorporating the SST$k-\omega$ turbulence model and the discrete phase model, were utilized to systematically investigate the pressure distribution, velocity field, streamline patterns, and performance characteristics of the mineral extraction pump under three operating conditions—low flow rate, rated flow rate, and high flow rate—while transporting mineral particles of three distinct sizes. The results demonstrated that the larger size of the mineral particles induced greater disturbance to the liquid phase. Under different flow conditions, the correlations between the particle size and both the head drop rate and power drop rate exhibited distinct characteristics. Experiments verified the rationality and precision of the numerical simulation approach. This study provides a methodological reference for analyzing the flow characteristics and performance output of deep-sea mineral extraction pumps.