Research On The Motion Characteristics And Winding Mechanism Of Flexible Fibers In A Vortex Pump

In the discharge and treatment of domestic sewage and industrial wastewater,the medium often contains a large amount of fibrous substances,which easily causes the blockage of the vortex pump and affects the operation stability of the pump unit.In order to study the problem of winding blockage in the vortex pump,this paper adopts the CFD-DEM coupling method and the soft ball model to calculate and analyze the motion characteristics and winding mechanism of the fibers in the vortex pump.The main work and results are as follows:(1)The comparative study found that the typical motion states of fibers in the cyclone pump are divided into four types: the first type is that the fibers leave the leafless lumen faster;the second type is that the fibers leave the leafless lumen more slowly;the third type is that the fibers are wound at the leading edge of the blade;the fourth category is that the fibers are wrapped around the tongue.(2)Comparing the motion of fibers at different phase angles,it can be found that when the through-flow and circulating flow in the bladeless cavity alternately exist,and the high-speed region and the low-speed region are evenly and symmetrically distributed,the fibers easily move to the trailing edge of the blade and show a strip-shaped radial pattern.Expand and finally leave the bladeless cavity;when the through-flow is gradually covered by the circulating flow,and the high-speed zone and the low-speed zone are asymmetrical,the pressure velocity in the flow field decreases,and the fibers move in a circular motion near the impeller inlet,and the fibers tend to be at the leading edge of the blade.Wrap around,or unfold axially near the septum tongue and wrap around the septum tongue.(3)The motion characteristics of fibers with different geometric parameters in the pump and their effects on the flow field are studied.The results show that the local pressure velocity of the flow field where the fibers are entangled will change.The change of pressure and velocity of the surrounding flow field is small;with the increase of fiber length,the fiber is wound around the leading edge of the blade and the separation tongue,and the change of the surrounding flow field increases;when the fiber length is greater than twice the inlet diameter,the fiber is easily wound around the pump shaft;When the length is the same,the increase of the diameter will lead to a decrease in the velocity of the flow field around the filament winding,making clogging more likely to occur.(4)Comparing the wear at the blade,it can be found that the higher the fiber speed,the higher the wear rate of the blade;while the wear at the tongue has little relationship with the speed,and the speed of the fiber at the tongue and the pump shaft is almost zero.,The wear is mainly caused by the friction of the fiber.The larger the diameter of the fiber,the larger the contact surface,the stronger the friction,and the more serious the wear on the separator tongue and the pump shaft.The research results provide a theoretical basis for improving the blockage of the vortex pump,improving the stability and service life of the vortex pump.