Performance of Fluid Flow and Mixing in Compartmented Agitated Tanks
|School||East China University of Science and Technology|
|Keywords||compartmented agitated tank residence time distribution mixing time drop size distribution Sauter mean diameter|
In this paper, the performance of fluid flow and mixing in agitated tanks with different compartmental pattern was studied systematically. The effect of disk styles and size on fluid flow and mixing characteristics was investigated by particle tracing, color tracing and electric conductivity tracing, and the amount of back-mixing was discussed according to mathematics model in axially compartmented tank with different kind of disks agitated by impellers. The results showed that reducing the opening size of disks could effectively decrease interstage back-mixing in low power input, but actual effect was not ideal in high power input.The effect of the connected forms of transversal compartmented agitated square tanks on back-mixing and impeller types on power and mixing time in single stirred square tank were discussed. The results showed that installing baffles in a square stirred tank could effectively eliminate centre vortex, but the baffle thickness variation had little effect on the impeller power number. Higher and lower off bottom clearance of the RT decreased the power number. Dimentionless mixing time of all impellers in a square tank was correlated, and the correlation was suggested as following:Nθ=6.31NP-0.096(Ts/D)1.33. The order of distributive range of droplet diameter and d32 was found to be following as Lightnin A315>PBTU I> RT in a stirred square liquid-liquid dispersion system.