Study On The Numerical Simulation And Visualization Experiment Of The Three-Dimensional Chaos Mixing Flow Field In Laminar Stirred Tank

Laminar stirred tanks are widely used in chemical engineering, biomedical engineering, pharmaceutical engineering, and material process. When the media in stirred tank are shear stress-sensitive, either the rotate speed or the Reynoles number is quite low, mixing is often inefficient. Generating a chaotic mixing in laminar stirred tank can effectively improve the mixing efficiency, shorten the mixing time, and have wild future in engineering application.In the paper, the studies of theory analysis, numerical simulation and experiment were done to reveal the form mechanism, mixing characteristic, influence factor and application in engineering of chaotic mixing in laminar stirred tank. The main content of the paper is as follows:(1)Introduce the theory of how chaotic mixing improve the mixing efficiency, bring forward an idea of aperiodic and dissymmetrical three-dimensional chaotic mixing, use the non-periodicity of impeller rotation and the dissymmetrical of impeller configuration and disposal in stirred tank to enhance the agitation of laminar fluid in stirred tanks, generate a three-dimensional chaotic mixing, improve the mixing efficiency.(2)Use CFD software to simulate the three-dimensional laminar mixing in stirred tank. Simulate the three-dimensional laminar flow field of four different conditions: the impeller with 6 bladed is concentric with the vessel, the impeller with 6 bladed is eccentric to the rotating axis and the vessel, the impeller with 6 bladed and the rotating axis are eccentric to the impeller, the impeller with 3 bladed is concentric with the vessel. Post-process and characteristic analyze the three-dimensional flow field, and explain the mechanism of dissymmetrical geometry figure generate three-dimensional chaotic mixing in laminar stirred tank.(3)According to analyze and compare the experiment results of three different cases: steady RPM, co-reverse periodic RPM, time-periodic fluctuation of RPM, qualitative validate the theory of using the non-periodicity of impeller rotation to enhance the agitation of laminar fluid in stirred tanks, generate a three-dimensional chaotic mixing, destroy isolated mixing regions which is bad to whole mixing in stirred tank, improve the mixing efficiency.