ABSTRACT:

A lab-scale flexible hose apparatus has been designed and manufactured to analyze the flowing characteristics of solid-liquid two-phase mixture in a flexible hose. The experiments for solid-liquid two-phase flow in a flexible hose has been performed by changing experimental factors, such as particle size, particle injection rate, hose shape and two-phase mixture velocity. The experimental results show that the increase of discharged volume fraction and diameter of the solid particles causes the pressure drop in the hose and the increase of the minimum velocity to transport the solid particles in the identical flexible hose. In the case of the solid-liquid two-phase mixture velocity more than 1.5 m/sec, the more the shape of the flexible hose becomes curved, the more the pressure drop in the hose increases. When it is lower than 1.5 m/sec, it was confirmed that the more the shape of the flexible hose becomes linear, the stronger the accumulation phenomenon becomes and the more the pressure drop in the hose increases.

INTRODUCTION

Lifting system technology, together with the collection system, is a very important field that determines the commercial value of the deep-sea mining and can be divided into the following 3 parts: pumping system(hydraulic pumping/air lifting system), buffer system and flexible hose system. The flexible hose system that connects the collection system and lifting system systematically plays the role of preventing the lifting pipe from getting twisted or broken by the influence of sea currents or up-and-down movements of the ship. On the contrary, if it is slow, the manganese nodules will be accumulated and close the hose. Therefore it is very important to fully understand the flow characteristics of the solid-liquid two-phase mixture according to the shapes of the hoses for the stable and effective management of the flexible system.

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