Experimental Study On Preparation And Magnetic Viscosity Characteristics Of Magnetic Fluid Hydraulic Medium

Hydraulic transmission has been widely used in various types of mechanical equipment due to its unique advantages such as high power density.Hydraulic working medium,as the medium for power transmission and control of hydraulic system,plays a crucial and decisive role in the system.Viscosity is one of the most important physical parameters of hydraulic media.However,the viscosity of the traditional hydraulic medium is too high in the low temperature environment,and the oil speed of the pipeline is slow.Due to the poor flow force of the medium,the pumping efficiency decreases,and the component microchannel cannot be obtained.The hydraulic medium is sufficiently lubricated to form dry friction,which causes damage to internal parts of the hydraulic components.The magnetic fluid is apparently a ferromagnetic fluid with magnetic field controlled rheology and thermophysical properties,and can be prepared as a magnetic fluid hydraulic medium having magnetically controlled properties.In response to the above problems,this paper replaces the traditional low temperature hydraulic oil with nano magnetic fluid to improve the viscosity characteristics of the hydraulic medium.This paper introduces the classification,performance and application of traditional low temperature hydraulic media and magnetic fluids,summarizes the research status of magnetic properties of nano-hydraulic media and magnetic fluids,and puts forward the idea of replacing magnetic fluids with traditional hydraulic media.In this paper,the sedimentation stability and magnetic viscosity characteristics of magnetic fluid are discussed from two aspects of theory and experiment.Theoretically,the basic mechanism and stability mechanism of magnetic fluid,magnetic magnetic viscosity characteristic mechanism of magnetic fluid are introduced,and the viscosity measurement method is introduced.The rotary viscometer is selected as the sample viscosity measurement method.In the experimental aspect,the nano-Ni_0.5Zn_0.5Fe₂O₄ magnetic fluid hydraulic medium was prepared by two-step method.By comparing and analyzing the magnetic fluid components,temperature,magnetic field,pH and other factors,the stability of zero magnetic field and magnetic field conditions was obtained at different temperatures.Good magnetic fluid.The magnetic viscosity characteristics of magnetic fluid were studied.The effects of dispersant type and mass fraction,magnetic particle size,magnetic field strength and action time,and liquid-solid phase transition on magnetic fluid magnetic viscosity were analyzed.The test results show that the viscosity-temperature characteristics of silicone-based magnetic fluid and hydraulic oil-based magnetic fluid are better than traditional low-temperature hydraulic oil in the absence of magnetic field environment,while the viscosity-temperature characteristics of silicone-based magnetic fluid are better,and the magnetic fluid is verified as the hydraulic medium.Feasibility in viscosity.In the magnetic field environment,the viscosity of the magnetic fluid increases with the increase of the magnetic field strength,and has better magnetic control performance.The magnetic field action time has no effect on the viscosity of the magnetic fluid,and the magnetic fluid hydraulic medium has a long service life in the magnetic field.