Study On Solid-liquid Two-phase Flow Characteristics Of The Large Size Blade Tornado Flow Stirred Tank

Solid-liquid mixing operation is widely used in some chemical process such as polymerization, fermentation, catalysis, crystallization and waste water treatment. The stirred tank studied in the text is based on central tornado flow stirred tank by Guo Duxin and Hao Huidi. It uses large size blade instead of conventional size blade. This paper studies the stirring and mixing characteristics of the turbulence characteristics from the critical suspension speed and power consumption. In this paper the stirred tank was studied by numerical simulation of CFD and experiments.This paper firstly studies solid-liquid two-phase flow characteristics of stirred tank through CFX software of ANSYS13.0, to seek optimized stirred reactor structure which can achieve good effect of solid-liquid suspension characteristics. By comparing different cross section and different axial cross section of velocity vector diagram, solid fractions contour, turbulent kinetic energy contour, it can qualitatively analyze the effect of different forms, different blade paddle installation height and different stirring speed on solid-liquid two-phase flow. The results show that:with open turbine blade with six leaves, the installation height of80mm, blade diameter of170mm, the height of the liquid level of200mm, reactor diameter of200mm, the stirring speed of250rad/min, the stirred tank can achieve good solid-liquid mixture effect, and tornado flow effect is obvious. The reasonable structure is established by numerical simulation, which provides the theoretical basis for the follow-up experiment.Experimental study was conducted in the structure determined by the numerical simulation, emphatically from the critical suspension speed and power consumption experiments. Finally we analyze the experimental results to get the change rule of different performance parameters, and fit the correlation of critical suspension speed:.Experiments show that:solid-liquid suspension performance of stirred tank reactor with large size blades is better than the stirred tank reactor with conventional size. Under the same conditions, the critical suspension speed of the stirred tank reactor with conventional size is smaller. Therefore,This research provides a theoretical basis for industrial structure optimization and scale-up of the stirred tank.