| Mixing equipment is widely used in all walks of life,in the metallurgical industry,neodymium-iron Borate solution stirring reaction device outputs are in rare-earth extraction source of liquid raw material in the production process.Its output of the feed efficiency and uniformity will affect subsequent extraction process of mixing efficiency.The mixing efficiency and mixing rate of equipment depends primarily on the internal fluid mechanical properties and flow characteristics,and performance characteristics of fluid and is closely related with blade structure and equipment configuration.At present,many scholars study the flow in a stirred tank mixing mainly through experiment and numerical simulation.Comparing two methods,numerical simulations have shorter development cycle,low environmental impact and low cost,have access to more data which were widely used as prerequisite for industrial application experimental study.The mixing characteristics of dual layer interlaced oar(two-layer is different plane vertical)in the agitation tank was studied by using numerical simulation package FLUENT.Combined with the actual production equipment to structure physical modeling,the standard k-? turbulent model and the multiple reference frames(MRF)were adopt in simulation.The work mainly as follows:Impeller diameter,impeller angle,interlayer distance of two impellers,low impeller from the bottom height and baffle width as a variable to the object of study,simulated the velocity field and turbulent kinetic energy changes under the single change of each variable,found that turbulent kinetic energy is related to the structure and position of the impellers,the impeller diameter main effects of turbulent kinetic energy range,the angle of impeller is focuses on the turbulent kinetic energy peak with great impact.Under the single changes in various factors,the power and influence of mixing time are analyzed.The results show that,with the recommended range of factors values,increases impeller diameter and impeller angle will make the equipment required to drive the power significantly increased,in addition,from widening the interlayer distance can also raise demand driving power but not obvious as diameters and angles are.Mixing time will shortened when the impellers diameter and angle are increase in a range of sizes,it will be appear a "bounce”,means the mixing will be increase when the impeller size over this range.By analyzed of stirred tank with two performance indicators: mixing rate and mixing efficiency,and there is a better interval about the diameter,the angle of the leaf for each other.When this factors in theirs best range the stirring performance evaluation is better.The multiple factors on mixing characteristics of stirred tank were analyzed,through using orthogonal test analysis method with the analysis software SPSS,and it was concluded that the primary factors affecting the agitated tank performance of the multi-factors were the diameter,secondary factors for impeller angle,according to orthogonal analysis results,using mixing time and mixing efficiency as the evaluation index on the blade size parameters are optimized,and the optimization impeller got better mixing performance index than the initial paddle leaves in different degrees.This study has certain guiding significance for the double hinge oar style mixing equipment research and optimization,and provide some references from the perspective of theoretical analysis. |
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