When the radial flow impeller rotates at a certain speed, the high-speed fluid is removed from the impeller. This high-speed fluid simultaneously attracts the liquid around the belt, causing the surrounding static flow or low-speed flow to be drawn into the high-speed flow. When there is no baffle in the tank, a horizontal circulation flow is generated. When the tank is equipped with a baffle, it forms a strong circulating flow along the wall surface and the stirring shaft. In order to distinguish it from the high-speed flow discharged from the impeller, it is called Secondary circulation flow.
The high-speed flow of the axial flow agitator from the impeller is axial, and it also has the effect of attracting the slings to the surrounding low-speed flow. The liquid discharged from the impeller transfers the energy from the impeller to all parts of the tank, and the liquid in the tank is sequentially circulated to the vicinity of the impeller with strong stirring action, so the discharge performance of the impeller is very important for the stirring process. . This volumetric circulation in the stirred tank is a macroscopic flow. However, in order to be effectively mixed so as to carry out other stirring operations such as heat transfer, mass transfer, dispersion, etc., it is also necessary to have a strong turbulent diffusion effect. When the flow is in the turbulent process, there are many vortices of various sizes in the flow field.