Influence of vane impeller with different surface structure on characteristics of stirred flow field
To enhance the turbulence intensity and mixing efficiency of the fluid medium,the surface of the agitator's blades was designed with a step-like structure.The conventional blade impeller and the stepped blade impeller were placed in the cylindrical cylinder,and the preliminary model comparison and verification were carried out through velocity field distribution,hot and cold water mixing and solid-liquid mixing analysis.Then the two types of blade impeller were applied to the actual high-efficiency sedimentation tank,and the simulation was carried out through 1∶1.The results show that boundary layer region of the stepped blade can produce more violent turbulent structure,and there are reflux vor-tices in front of the facing water of each step,whose flow characteristics are extremely complex,which is conducive to promoting the local mixed reaction.With a large amount of energy input,each phase medium is affected by the impact and extrusion of the step surface,which makes the mixing effect of hot and cold water and solid-liquid phase more uniform.This effect is particularly significant in the simulation of low speed(60 r/min).In the simulation of the actual high efficiency sedimentation tank,at 56 r/min,the average flow velocity of the flow field in the flocculation zone is 0.152 m/s when the stepped blade is used,and the average flow velocity is 0.137 m/s when the conventional blade is used,and the turbulent kinetic energy dissipation of the stepped blade is significantly higher than the latter.Therefore,in the application scenario of low rotational speed,the mixing effect of stepped blade is ob-viously better than that of conventional blade.The research results have positive significance for the op-timization of coagulation process,and provide a design idea for the development of new type stirring impeller.
agitatorstepped bladeflow field characteristicsfluid simulationheat exchange
万方数据
维普
