The Experiment Study On The Flocculation Vortex Hydrodynamics Of Adjustable Flocculation Tube

The traditional static mixer can’t adjust according to the actual working conditionin water treatment which result in unstable water quality. This is a widespreadproblem. This paper introduces a new adjustable flocculation tube on the basis of thecoagulation vortex theory. This flocculation device can enhance the flocculation effectbeside the adjustable character.The design principle of the adjustable flocculation tube is firstly explained andthen the mechanical structure of the adjustable flocculation tube is presented.Secondly, the performance of the adjustable flocculation tube is studied and the testresults are analysed. The test mainly study the influence on the coagulation process ofdifferent vortex which is produced by different velocity of flow and blades’ rotationangle. Turbidity of effluent, zeta potential and pressure loss, which are obtained byexperiment, are the criteria of quality of effluent, mixing effect of coagulation andwater and energy consumption level. Due to the differences in experimentalconditions and actual water plant operating conditions, the experimental results can’tcompletely reflect the practical application effect of the adjustable flocculation pipe.So the performance of the adjustable flocculation tube can be verified by contrast test,namely comparison of mixing tube section of adjustable flocculation tube and the SKstatic mixer, flocculation tube section of adjustable flocculation tube and tube withoutany component.The result indicate that the coagulation effect is not only depends on the mixingeffect of flocculant and raw water, but also determined by promotion of vortex toparticle collision and the shearing force to alum blossom of turbulent shear force. Theadjustable flocculation tube can be adjusted according to the actual working conditionand improve the coagulation effect. Moreover, operation requirement of adjustableflocculation tube in different working condition is obtained..The vortex intensity will be stronger and the eddy scale larger when the rotatingangle is larger and the velocity of flow higher. Results of zeta potential shows that thishydraulic condition favours the mixing effect of flocculant with raw water, but resultsof turbidity indicate that as the strong shearing force to alum blossom caused bystrong intensity vortex, quality of effluent is poor. The removal rate of turbidity of the mixing tube section of adjustable flocculation tube is higher than the SK static mixerwhen the flow rate is low. But when the flow rate is high, the latter’s coagulationeffect is better as the strong shearing force to alum blossom caused by strong intensityvortex. Pressure loss of the mixing tube section which consists of four vortexgenerators is higher than the SK static mixer when the blades’ rotation angle is high.So the suitable arrangement of blades’ rotation angle is15°~30°.Micro-eddy generated by vortex-generator with twelve blades can effectivelyimprove the coagulation effect. Therefore, quality of effluent of flocculation tubesection of adjustable flocculation tube is better than that of tube without anycomponent. The suitable arrangement of blades’ rotation angle is10°~30°. The blades’rotating angle should be larger at low load working condition of water treatmentplants; otherwise the angle should be small.