Analysis of air column formation and high-efficiency density separation processhe heavy medium hydrocyclone is a coal preparation equipment with a simple structure, no moving parts, and high sorting efficiency. Due to the lack of moving parts in the hydrocyclone, its sorting process relies entirely on the flexible combination of its own structural parameters and external operating parameters to achieve optimal sorting accuracy. This is a prominent feature that sets hydrocyclone coal selection apart from other coal selection methods.
In the separation process of heavy medium hydrocyclone, materials and suspensions are fed into the hydrocyclone at a certain pressure along the tangential direction, forming a strong vortex flow; The liquid flow starts from the inlet and forms a descending outer spiral flow along the inner wall of the hydrocyclone; Form an upward internal spiral flow near the axis of the hydrocyclone; Due to the negative pressure of the internal spiral flow, air is sucked in, forming an air column at the axis of the hydrocyclone; The clean coal in the feed flows upward along the inner spiral and is discharged from the overflow outlet, while the gangue flows downward along the outer spiral and is discharged from the bottom outlet. The formation mechanism of the air column is as follows: due to the direct connection between the bottom flow tube and the overflow tube and the atmosphere, the two-phase flow entering the hydrocyclone moves in a strong spiral vortex motion. When the tangential velocity increases to the critical velocity, a certain resistance is generated at each outlet of the hydrocyclone, forming an internal rotating flow field and inducing axial negative pressure. Air enters the hydrocyclone through the overflow tube and bottom flow tube, and gradually develops into a continuous air column under the joint action of axial negative pressure drive and fluid convection transmission. When the particle density is greater than the suspension density, the resultant force acting on the particles at a radius of r in the suspension is positive, and the particles are thrown out into a spiral flow; Otherwise, the particles will be thrown into an inward spiral flow; Thus separating particles with a density greater than the medium from particles with a density less than the medium. In the hydrocyclone, centrifugal force is several to tens of times greater than gravity, greatly accelerating the sorting speed and improving the sorting effect.
