Research on the motion of particles in fluid conveying is significant for the mechanism study of the hydraulic collecting process in deep-ocean mining. Experiments were conducted in a water tank to measure the translational and rotational motion of spherical particles by developing a spherical detector with a built-in three-dimensional acceleration microsensor and a three-dimensional microgyroscope. The three-axis linear acceleration and angular velocity can be measured and stored by the detector. The attitude angle, defined as the spatial rotation of the detector coordinate system relative to the laboratory coordinate system and described via the Euler angle, is obtained with a quaternion algorithm and a Kalman filter. The method is validated with a 50 mm diameter spherical object by three respective tests. Finally, the detector is tested as a tracer particle in hydraulic collecting. Findings indicate that the method is capable of tracing the detailed behaviors of particles in hydraulic collecting.
In the process of exploring and developing the ocean, human beings have found that the seabed contains extremely rich metal mineral resources, oil, natural gas hydrate, etc., which can be of many types, be found in huge reserves and high grades, and have great prospects for development and utilization (Lusty and Murton, 2018). A deep-sea mining system is an integrated unit of mining vessel, pipe, and mining vehicle on the seabed that picks up solid particles or alluvial forms of solids, including heavy mineral particles, from the deep seabed and transports the solid particles to the sea surface. The mineral particles are mostly spherical or ellipsoidal, with their long-axis length varying from 2 cm to 10 cm, and the hydraulic lifting process is the large particle solid-liquid two-phase flow (Li and Chen, 2003). The movement mechanism of particle-water mixture is the key to hydraulic lifting technology.