Effect of Rheological Property of Fluids on Mixing Time in a Stirred Vessel

Aizawa, Eiji; Sakano, Nobuhiro; Imakoma, Hironobu; Ohmura, Naoto

doi:10.1252/kakoronbunshu.35.539

Cited by 5 publications

(1 citation statement)

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“…Numerous research reports have been published on the mixing times of stirred tanks with other types of impellers. The mixing time in a stirred tank can be measured experimentally using the electron conductivity method (Bujalski et al, 2002a;Giona et al, 2002), decolorization method (Aizawa et al, 2009;Takahashi et al, 2012), electrical resistance tomography (Rodgers et al, 2009(Rodgers et al, , 2011, planar laser induced fluorescence (PLIF) (Zadghaffari et al, 2009;Hu et al, 2012), and thermographic technique (Lee and Yianneskis, 1997). Ascanio (2015) summarized the methods, theories, and advantages and disadvantages of these experimental measurement techniques in detail.…”

Section: Introductionmentioning

confidence: 99%

Mixing Process in a Tank Stirred with Improved Double Intermig Impellers

Zhou

Wang

et al. 2019

J. Chem. Eng. Japan

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The mixing process in a 0.42-m diameter transparent stirred tank with improved double Intermig impellers was experimentally studied using the decolorization method with four di erent tracer injection points. The time dependence of the tracer concentration distribution was recorded using a high-speed camera. The turbulent ow and tracer dispersion were calculated by a large eddy simulation (LES) combined with the dynamic Smagorinsky-Lilly model. The tracer di usion process, tracer concentration response, and mixing time in the tank stirred with the improved double Intermig impellers were investigated. The results showed that the mixing process predicted by LES was consistent with that by the decolorization method experiment. The predicted mixing time was 14% longer than the experimental time. The mixing time was the shortest when the injection point was in the middle of two impellers. The mixing time increased when the injection point moved to the top or bottom of the tank. The mixing times at the monitoring points near the injection point were shorter than those at distant points. The bottom of the tank with the improved double Intermig impellers was the crucial region that was di cult to mix. The mixing times at the monitoring points at the bottom were the longest for all the injection points. Increasing the mixing speed could promote the mixing process of the medium in the stirred tank and reduce the mixing time without changing the ow eld structure. Therefore, the results could serve as a guide for the design and engineering application of such a stirred tank.

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