Research On Magnetic Fluid Sealing Liquid Medium Based On The First-order Buoyancy Principle

One of the main applications of magnetic fluid is magnetic fluid seal,which has the advantages of long life,zero leakage,no pollution,and is therefore widely used in gas and vacuum seals.With the in-depth study of magnetic fluid seal,its range of applications continues to expand.In the fields of petrochemicals,marine engineering,etc.,it is necessary to complete the seal in a liquid environment.In the liquid sealing process,the magnetic fluid directly contacts the liquid to be sealed,which causes emulsification,and it is difficult to ensure the sealing performance of the magnetic fluid.In order to solve the problem of magnetic fluid sealed liquid medium,this paper proposes a new solution:the non-magnetically conductive solid particles are added to the magnetic fluid,and the non-magnetically conductive solid particles are discharged to the surface of the magnetic fluid by the first-order buoyancy principle of the magnetic fluid,thereby weakening the direct contact between the magnetic fluid and the sealed liquid,and improving the sealing performance of the magnetic fluid.This paper mainly carried out the following work:(1)According to the main failure mechanism of the magnetic fluid sealing liquid,a method of solving the problem by using the first-order buoyancy principle of the magnetic fluid is proposed:the non-magnetically conductive solid particles are added to the magnetic fluid,and the non-magnetically conductive solid particles are discharged to the surface of the magnetic fluid by the first-order buoyancy principle of the magnetic fluid,thereby weakening the direct contact between the magnetic fluid and the sealed liquid,and improving the sealing performance of the magnetic fluid.(2)Comparing the characteristics of different kinds of magnetic fluid,it is necessary to ensure that the magnetic fluid does not interact with the liquid medium to be sealed.According to the physical and chemical characteristics of the liquid medium to be sealed in this paper,an oil-based magnetic fluid is selected.(3)The interface observation experiment platform was built to study the sealing mechanism of magnetic fluid with non-magnetically conductive solid particles.It is concluded that the volume of the magnetic fluid under the monopolar pole teeth is an important factor affecting the liquid seal.The tendency of the magnetic fluid seal change process to add non-magnetically conductive solid particles is consistent with conventional magnetic fluid,which can attenuate the interaction between the magnetic fluid and the sealed liquid during the sealing process.(4)The liquid seal test piece was designed,and the pressure resistance capacity of the pole piece was simulated by using the software ANSYS.Considering the relationship between the failure of the liquid seal and the magnetic fluid quantity under a single pole tooth,the tooth width was finally determined to be 0.5mm.(5)A magnetic liquid sealing test bench was built,and the pressure test and sealing time of the magnetic fluid with non-magnetically conductive solid particles were tested.Experiments have shown that the addition of non-magnetically conductive solid particles has little effect on the pressure resistance of magnetic fluid.The addition of non-magnetically conductive solid particles weakens the direct contact of the magnetic fluid with the liquid medium being sealed,and the sealing time is increased by up to 21.5%compared to conventional magnetic fluid.48 figures,14 tables,57 references.