Research on erosion characteristics of deep-sea sediment:Coanda-effect-based hydraulic collector
Deep sea harbors abundant mineral resources,and the exploitation and utilization of metal manganese nodules will effectively address the issue of terrestrial resource scarcity,thus attracting widespread attention worldwide.The Coanda-effect-based water jet,as one of the mainstream methods for nodule mining,has an unclear coupling mechanism with the deep-sea sediment,which significantly hampers the nodule collector optimization.This study,via simu-lations and physical model tests,investigated the influence of three factors:Nozzle height,jet flow speed,and guide plate curvature on the hydraulic intensity of erosion and erosion shape.Within the experimental range,the erosion characteristics of the Coanda-effect-based hydraulic collection method on deep-sea sediment were clarified.Then,the jet parameter combination corresponding to the best hydraulic intensity of erosion was identified.The test results show that the erosion pit is generally elliptical,and its overall position is towards the left side of the jet impact center area.The cross-sectional profile is U-shaped and the pit bottom is irregularly protruding or recessed.The influence of nozzle height on the hydraulic intensity of erosion first increases and then decreases.The jet flow speed is positively correlated to the hydraulic intensi-ty of erosion,while the influence of the guide plate curvature on the hydraulic intensity of ero-sion shows a negative correlation.In this paper,the jet parameter combination corresponding to the highest hydraulic intensity of erosion is a jet speed of 5.31 m/s,a nozzle height of 60 mm,and a guide plate curvature of 0.010 mm-1.These works are hope to provide a theoretical reference for revealing the jet erosion mechanism and the nodule stripping mechanism.
nodule hydraulic collectionCoanda-effect-basederosion characteristicshydraulic intensity of erosion
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