| The stirred reactor is the widespread applied reactor type in the process industry, and it takes a leading position in chemistry and chemical industry. In a long period, scholars from different countries have taken lots of deep researches on the flow field characters of stirred tank, and more and more scholars become cognizant that it's important to obtain flow information accurately in reactor for optimizing design and developing new stirred reactor.This paper firstly has researched the inner flow field of a stirred reactor assembled with flat blade impeller and 45°angle pitched impeller respectively, and used experiment results obtained by PIV system to check the reliability of FLUENT simulation results. Then, used software FLUENT to further research and analyze the flow field character parameters such as macroscopic regularity, velocity character, turbulent performance, shear performance and power consumption, and obtained such conclusions as following:1. Through the qualitative and quantitative analysis on macroscopic regularity and velocity character of flow field in stirred tank, it's showed that the flow field character and data curve obtained by two methods are basically same, the numerical simulation method used in this paper is feasible, and the results are reliable. The flow field treating methods such as MRF, RNG k-e turbulent model and boundary conditions selected in simulating process have perfect adaptability for flow field analysis in stirred reactor.2. The "two circulation flow" formed by flat blade impeller is obviously different from the "whole circulation flow" formed by 45°angle pitched impeller, so they express different effect to fluid: flat blade impeller with radial flow chiefly generates shearing effect to fluid, and 45°angle pitched impeller with axial flow chiefly generates circulation effect to fluid.3. In stirred tank, the turbulence kinetic energy mainly generates in the region around impeller, and the turbulence kinetic energy also mainly dissipates in this region, so it's showed that the turbulent degree is much stronger and mixing effect is much better in this region. The turbulent performance of flat blade impeller is obviously better than that of 45°angle pitched impeller, and it's showed that the shearing, breaking and scattering effect of flat blade impeller is better than that of 45°angle pitched impeller.4. In stirred tank, the shearing effect mainly generates near the impeller, and it depends on shearing effect to scatter and mix material thoroughly in the region around impeller. In general the shearing rate of flat blade impeller is much larger than that of 45°angle pitched impeller, especially in the impeller edge region.5. Although 45°angle pitched impeller have less shearing capability, it can save almost 40% power consumption than flat blade impeller, and obviously it is better than flat blade impeller in economy.6. The flat blade impeller and 45°angle pitched impeller have different mixing operating characters: flat blade impeller chiefly generates radial flow, high shearing effect, high turbulent degree, is suitable for breaking and scattering material in stirred tank, and belongs to shearing type impeller; 45°angle pitched impeller chiefly generates axis flow, strong entirely circulating capability, relative low power consumption, is suitable for homogenizing and mixing material in stirred tank, and belongs to circulating type impeller. It should choose different types of impeller for different mixing requirements and operating conditions. If require stronger shearing effect, shearing type impeller should be chose; if shearing effect is not required so much, and only the requirement of material entirely mixing, circulating type impeller should be chose, under saving power consumption.7. It can be more economical, fast and reliable to design, optimize and select for stirred reactor using FLUENT simulation software combining with PIV measurement system.
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