Experimentation Research On Magnetic Fluid Viscosity Drag Reduction

Drag reduction is always a popular field in science research.The reason lies in that it has the wide applications and important academic merits.Magnetic fluid viscosity drag reduction is a new type of drag reduction method which has so many advantages as simple structure,exeeUent controllablility,long life,far using range, etc.The work of this paper is focused on experiment,theory and numerical simulation of drag reduction research.In the part of experiment,Kerosene-based & water-based magnetic fluid are prepared and drag reduction structure which can keep magnetic fluid coat stabilization is designed.At meanwhile,the process of magnetic fluid coat distortion,stabilization & breakage are observed by magnetic fluid coat breakage experiment,so the condition of interface stabilization between magnetic fluid and viscosity fluid is confirmed.Optimal thickness of magnetic fluid coat is validated in the course of drag reduction by coat influence flux experiment.The effect of drag reduction is improved by 5.5%～9.5% during the magnetic fluid viscosity drag reduction experiment is fulfilled on the self-designed test-bed.The relationship between surface area of magnetic fluid coat and the effect of drag reduction is confirmed,and the relationship between the entrance velocity of viscosity fluid and the effect of drag reduction is confirmed.In the part of theory,circumfluence phenomenon inside magnetic fluid coat is confirmed.Analytic formula of velocity inside magnetic fluid coat is deducted.In the part of numerical simulation,magnetic-circuit of drag reduction strcture and viscosity fluid laminar flow are analysed within magnetic field and flow field by ANSYS finite element software.Math-model of magnetic fluid flow in the pipeline is designed in order to observe motion state of magnetic fluid coat.The measurement result of magnetization curve of magnetic fluid is fitted in an anti-tangent function by function optimum- approach method.Magnetic field and flow field are coupled by substituting magnetic fluid magnetization-strength & vol-force function into Navier-Stokes function.The entrance velocity of magnetic fluid flowing in the pipeline with half-sine wave function is analysed by coupling function and written into Comsol Multiphysics software.The results show that a part of magnetic fuid are adsorbed by pipeline wall,or slowed down by the magnetic vol-force on the mgnetic fluid which brings out decreasing fluid flowing area and increasing velocity of magnetic fluid on the middle part.Motion of magnetic fluid is agitated rather than stopped in local eddies by the magnetic vol-forces which is working on the magnetic fluid,even though the entrance velocity of magnetic fluid is zero.There are 92 figures,16 tables,112 references on this paper.