Exploration On Performance Of A Coaxial Mixer With Dual Shafts In Highly Viscous Newtonian Fluids

With the development of mixing device to be bigger, more intelligent and efficient, the traditional agitator gradually can not be qualified to work well to satisfy some special need of industrial application. Therefore, to explore the novel structure and type of mixer is a beneficial method to solve this problem.This thesis discusses in detail the performance of a coaxial mixer operating in co-rotation and counter-rotation ways, which consists of a centered impeller(inner impeller) with a scraping anchor arm(outer impeller) rotating at different speed ratio. The inner impeller includes3kinds of single layer turbines and4kinds of dual layers impellers on the centered shaft. Meanwhile, the CFD has been used to investigate the power consumption, flow characteristics and mixing effect in the highly viscous Newtonian fluids, then the experimental and numerical results are compared.In view of power consumption, Results find out that power consumption of outer impeller is influenced largely by inner impeller but outer impeller has little effect on power consumption of inner impeller. Moreover, operation mode, speed ratio and layers of inner impeller affect differently the overall power consumption of coaxial mixer. From the aspect of flow patterns, Numerical result suggests that layers, diameter and operating mode can influence global distribution of flow. Speaking of the mixing performance, both experimental and numerical data show that the co-rotation mode works better as well, but such geometrical parameters as the bottom clearance of single layer impeller or the distance between two layers impeller should be choosed carefully. However, it must be pointed out that the mixing time has a relationship with the monitor point and feeding point of tracer in simulation.Through both experimental work and numerical study, this paper optimizes the configuration of coaxial mixer and can also provide guidance for its design and use.