Design And Output Characteristics Of Radial Gap Adjustable Magnetorheological Valve

Magnetorheological fluids(MRF)is a kind of intelligent fluid based on magnetorheological effect,which is mainly composed of soft magnetic particles,base fluid and surface additives.Its physical properties can be controlled by magnetic field,and it is widely used in semi-active,vibration control and other fields.MR valve is a new type of intelligent hydraulic control element designed based on the magnetorheological effect of intelligent material MRF.It has the advantages of no relative motion valve core,simple structure and fast response speed,and has a broad application prospect.Therefore,the preparation of MRF and MR valve are thoroughly researched in the dissertation.,the main contents are as follows:(1)This paper discusses the working principle and mode of MRF,analyzes the preparation of MRF and the research status of MR valve at home and abroad.According to the characteristics of MRF,the components of MRF were classified and screened.A variety of MRF were prepared by base fluid displacement method.The effects of different single surfactants on the settling stability and zero field viscosity of MRF were studied,and the law of the effect of each surfactant on MRF was obtained.(2)A radial gap adjustable MR valve was proposed.The flow path gap structure,the width of the flow path gap,the composition materials,the magnetic circuit and other key elements were optimized.The magnetic circuit was calculated and analyzed based on the basic theory of electromagnetic fields.And check the size of the magnetic circuit.According to the designed radial gap adjustable MR valve structure,the mathematical models of the pressure drop of the three gap channels were established,and the pressure drop calculation analysis was performed.(3)The magnetic field simulation of the radial gap adjustable MR valve was performed using the finite element software Ansoft Maxwell.The influence of input flow rate,the size of magnetic isolation ring and the size of flow gap width on the pressure drop performance of the MR valve under different excitation currents is studied.The results show that: 1.The yield voltage drop is only related to the change of current,and has nothing to do with the flow rate.The viscosity pressure drop is proportional to the flow rate.2.The maximum pressure drop is 3372 kPa for the radial gap adjustable MR valve with a section length of 7 mm and a width of 9 mm.3.The pressure drop increases with the increase of current in different radial gap sizes,and the smaller the radial gap is,the greater the pressure drop is.When the radial channel gap is 0.5 mm,the maximum pressure drop is 7095 kPa.when the radial channel gap is 2 mm,the maximum pressure drop is 2260 kPa.(4)The dynamic performance test platform of MR valve is designed and built.The performance test of the designed MR valve with adjustable radial gap is carried out.The variation of pressure drop at the inlet and outlet of the MR valve with current under different loads and different radial gaps was tested.The results show that the change of load size has no effect on the pressure drop,and the pressure drop increases with the increase of current at different radial gap,and the smaller the radial gap is,the greater the pressure drop produced by MR valve is.When the radial gap is 0.5 mm and the current is 1.5 A,the pressure drop of the MR valve with adjustable radial gap is the largest,with the value of 5138 kPa.Comparing the experimental results with the simulation results,it can be concluded that the change trend of the two is basically the same.When the exciting coil current is small,the experimental results are slightly lower than the simulation results.With the increase of the current,the experimental results are more and more lower than the simulation results.