The Study On Numerical Simulation And Flocculation Experiment Of The Taylor-Couette Vortex Flow

This article adopts Particle Image Velocimetry(PIV)and numerical simulation(CFD)methods to measure Taylor-Couette flow field,which compares and analyzes the results of the PIV measurement and numerical simulation,serving as a proof of the feasibility of exploring the Taylor-Couette flow field by means of numerical simulation methods.By different assessment indicators like velocity vector field,turbulent kinetic energy and turbulent dissipation rate,vorticity and velocity in different directions along different characteristic lines,and by a comprehensive comparison of numerical simulation results from Taylor-Couette reactor model under different geometric structures,the following conclusions are yielded:1.By comparing velocity vector chart of Taylor-Couette flow field under different geometric structures,it is found that no matter under which scale,the vortex flow fileld of Taylor-Couette model can always be divided into four sections according to its characteristic,and the velocity vector chart in different section possesses the following features: within the first section,the vortex volume is comparatively small,the morphology and size of the vortex is unstable in general;within the second section,the vortexes are arranged in order,of which the length and size maintain unchanged and the vortexes in vicinity are axially symmetric;within the third section,the form the character of vortex alter;within the fourth,the size of vortex keeps changing with respect to Reynolds number,and the length of vortex is prolonged to a further extent,the vortex center is gradually vague,resulting in the corruption of the vortex form in the end.2.Judging from the turbulent kinetic energy nephogram,the division appears in the turbulent kinetic energy of different models,in which the turbulent kinetic energy nephograms have their own characteristic in different sections,and the Reynolds number in turbulent kinetic energy nephogram roughly equals to the Reynolds number in velocity vector chart in different section,confirming the accuracy of division from a side-angle.3.It is found that,after comparing different vorticity isolines of models in different geometric structures,the vorticity isolines will form a vortex structure,where the vorticity value of adjacent vortex is inverse with each other.Along the direction from vortex center to the side,the vorticity value declines first and augments then,maximizing at the vortex center and side.As the Reynolds number inclines,the vorticity value as a whole manifest an up-going tendency.The bigger the Reynolds number,the larger the vorticity value.Meanwhile,the inclination of Reynolds number witnesses the similarity between the vorticity isolines and velocity vector chart in different models,which forms four distinctive sections.In the same model,the different section formed by vorticity isolines and velocity vector chart share the Reynolds number section,which proves the correctness of such division again.4.Through analyzing of vortex form,turbulent kinetic energy and vorticity isolines,the vortex flow field can always be divided into four sections.Contrasting the radial velocity and axial velocity along respective characteristic lines in different sections,the velocity distribution of different sections features differently,which are: when the vortex settles in the first section,the velocity is generally small and the velocity augmentation of different Reynolds number is big;when in the second section,the velocity is comparatively distributed in regularity,and the augmentation of different Reynolds number is similar,so as its distribution tendency;when in the third section,the velocity of different Reynolds number begins to fluctuate,which shows in two aspects: one is the fluctuation in velocity augmentation,which is uncertain;the other is in velocity value;when in the fourth section,the velocity value in different directions is comparatively large and has fierce fluctuation.5.By ways of comparing the velocity vector chart,turbulent kinetic energy,vorticity and velocity vector field,we found that no matter under which scale the Taylor-Couette model is,its vortex flow field can be divided into four different sections,which can be mutually proved by different assessment indicators all above.When the vortex flow field is located in the same section,the different features within the flow filed are similarly distributed and differ with other sections.