PIV Experimental Study Of Flow Field Of The Helical Ribbon-Anchor Impeller Stirred Tank

A polymerization reactor with a stirring device plays an important role in the production of the processes of chemical products such as resin, plastic and ethylene. The technology of PIV methods is used in this thesis to investigate the nature of the flow field like the turbulent kinetic energy and the root mean square speed of a polymerization stirred tank to give a guidance of the optimization and improvement of this style of experimental device.The experiment is accomplished in a stirred tank with a diameter of476mm and a standard elliptical bottom. The main research project is the nature of the flow field of the agitators consist of a helical ribbon impeller and a anchor impeller, H=570mm. The paper mainly analysis the distribution of analytical velocity, turbulent kinetic energy and the root mean square velocity of three different areas of the stirred reactor by changing the Reynolds number with different working mediums and rotation speeds.Studies have shown that the fluid shows a cycle of axial in the stirred reactor in the promotion of the rotating blade in the laminar flow region. In the same working medium, fluids are similar in different Reynolds numbers, but the radial velocity is influenced obviously at the impeller region, the axial velocity is influenced obviously at the axial region. In the transition flow region, the fluid flows in complicated cases, some small swirls are appeared around the blade. It is beneficial to the mixing. The extremum of radial and axial velocities are almost equal so the two different direction of fluid is both important.The paper also analysis and compare the nature of the flow field of laminar flow region, transition flow region and turbulence flow region. For the same working medium, the influence of the root mean square speed is not obviously with the change of the Reynolds number by changing the rotate speed.But when the working medium is changed, the root mean square speed change greatly. To the different working mediums, the size and the location of the swirl both change. In addition, the different pulse time△t and query region is also investigated in the thesis.