Study On Columnar Particles Solid-liquid Two-Phase Flow In A Deep-Sea Mining Lift Pump

The deep sea is a treasure house of human resources,and the 21 st century is the century of ocean development.The deep-sea mining pump is a key power component in the deep-sea mining system.Due to the complex and diverse conveying media,it is easy to cause damage to the internal components of the pump.In the study of solid-liquid two-phase flow,spherical particles are basically used,while non-spherical particles are mostly used in practical engineering.Therefore,this paper takes the columnar particles as an example to study the solid two-phase flow of non-spherical particles in the pump,and explore the motion characteristics of the columnar particles in the pump.With the support of the National Natural Science Foundation of China(51979124),this paper studies the solid-liquid two-phase flow of columnar particles in the deep-sea mining pump by combining experimental testing and numerical calculation.The inner flow characteristics of the particles,as well as the movement characteristics of the particles with different physical parameters,such as the movement trajectory,movement speed,over-pump duration and collision law.The main work and main conclusions of the paper are as follows:1.The force of spherical particles and cylindrical particles flowing in solid-liquid two-phase flow pump is theoretically analyzed,and the difference of force is compared.By comparing the force levels of particles,the forces that have little influence on the movement of particles are removed,so as to optimize the force conditions of particles with different shapes and the governing equations of fluid and particles.2.A visual test-bed for solid-liquid two-phase flow of ore lifting pump was built to test the external characteristics of the model pump when transporting clean water under different working conditions and particles with different physical parameters,The energy performance changes of clean water and particles with different shapes(spherical and cylindrical),cylindrical particles with different density and cylindrical particles with different concentration under different working conditions are analyzed.3.Using high-speed photography technology,visual experiments were carried out on the motion characteristics of particles under different physical parameters in the single channel of the first stage guide vane and the secondary guide vane of the model pump.The motion characteristics of particles with different shapes,densities and concentrations in different guide vanes were experimentally studied,and the motion trajectories,velocity,pump passing time and collision laws of particles with different physical properties were obtained.4.The CFD-DEM coupling calculation method is used to calculate the flow field in the pump when the pump transports particles with different physical parameters.The external characteristics of the pump and the motion law of particles are analyzed..