Structural Parameters Optimization Of Punched Impeller

Mixing equipment is one of common unit operation equipment in Process Industry.,so study of energy efficient impellers is very important. Punched impeller cansignificantly reduce power consumption and strengthen the stirring effect. Aiming at thecommon liquid-liquid phase stirred tank, based on advanced flow field test and CFDnumerical simulation technology, numerical simulation and experimental research havebeen taken on structural parameters of punched impeller within specific stirred tank.When dealing with similar stirred tank, the shaft, agitator and surrounding area are set tobe moving area by model simplified, based on tetrahedral mesh of the model grid. Thestandard k-ε turbulence model and moving reference frame (MRF) is used to solvesteady-state mixing flow field.Numerical simulation was taken about punched impeller structural parameters ofhole-position, opening rate and hole diameter,which was based on a specific size ofpitched blade paddle mixer under300rpm.Mixing coefficient K=×v/P had beenintroduced to evaluation the pros and cons of stirrer from the mixing effect and powerconsumption. Computer test system had been developed to test the mixing time.Experiments of mixing time and mixing power had been taken and numerical resultswere well verified by the experiment results.Compared with traditional paddle stirrer, punched impeller can strengthen the eddydiffusion and reduce blade projection plane and get a better mixing effect and lowerpower consumption, as the speed increased, the mixing power reduced the more obvious;Under the same hole diameter and opening rate, the further of the distance between holeand the axis, the smaller of the mixing power and the better of the as the speed increased,the mixing power reduced the more obvious, as the speed increased, the mixing powerreduced the more obvious; The mixing power and mixing time changes depends on the hole diameter and the opening rate, when the rate is around12%and the diameter isaround8mm,the mixing power and the mixing time is minimum, the result is best.The general method of modeled and analysis on tank can be extended to some otherfamiliar work.；The preliminary conclusion of specific tank with punched impeller lay the foundationfor the further study of tank amplification with punched impeller and engineering application.