Numerical analyses on the solid-liquid flow have been performed to design a lifting pump, which consists of two stages of impellers in series. Eulerian multi-phase model was applied using a CFD model. From the analyses, it was observed that backward flow occurred at the second stage of the lifting pump. No serious accumulation or plugging phenomena of solid particles did not occur in the first stage, but some accumulation area showed up at the second stage. It is suggested to reduce the numbers of the blade for the prevention of partial accumulation that can happen in the second stage impeller.
The deep sea floor could be thought as the last treasury of mineral resources to be left for mankind. The advanced countries have already driven forward actively the development of deep sea mineral resources in preparation for the on-land mineral resource exhaustion since 1960's. Especially, the successful development of deep sea manganese nodules requires developing exploration, mining and transfer technologies simultaneously, among which mining technology includes collecting and lifting technologies of the manganese nodules (Chung, 1994). Lifting system is crucial to achieve the success of the deep-sea mining project, by which manganese nodules are conveyed from the seafloor to the mining ship. The conveying principle can be classified into the hydraulic pumping system and the air lift system according to the fluid dredging type, the continuous line buckets system of the mechanical type and the modular marine mining automation system (Yoon et al., 2003). Among the lifting methods, the hydraulic pump lifting system is situated between the buffer system and the lifting pipe that is connected to the mining ship. The lifting pump, one of the core parts in the hydraulic pump lifting system, need to be designed with multi-stages because it requires a high hydraulic head.
