Publication Details

Hu, G., Li, H. & Li, W. (2016). Comparison and experiment of pressure drop of radial and annular type magnetorheological valves. Nongye Jixie Xuebao/Transactions of the Chinese Society for Agricultural Machinery, 47 (4), 364-371 and 405.


The magnetorheological (MR) valve is a smart control mechanism using the magnetorheologcial fluid as the working fluid. The advantages of regulating pressure drop and fast response time make the valve have a promising application prospects in the hydraulic servo system, and the MR valve can also be used as a bypass valve to control the MR damper, which can be applied to the different types of vibration attenuating system. The change of pressure drop of MR valve considering radial and annular fluid flow paths was outlined through theory analysis, numerical simulation and experimental verification. The magnetized resistance gaps of both MR valves were constrained within a width of 2.5 mm and a length of 80 mm. The mathematical models of pressure drop of both MR valves were derived separately. The finite element modelling was carried out using ANSYS/Emag software to investigate the distribution of magnetic flux density and dynamic yield stress, and the analytical pressure drop was also obtained, the maximum theoretical pressure drops for the radial and annular type MR valves are 1930 kPa and 982 kPa respectively. Furthermore, a test rig was set up to test the pressure drop under different applied direct currents and different load cases, the maximum experimental pressure dropts for the radial and annular type MR valves are 950 kPa and 660 kPa, respectively. The simulation and experimental results showed that the pressure drop of the radial type MR valve was superior to that of annular type MR valve under the same geometry conditions and the same electromagnetic parameters. The results can provide a new guideline for design of other types MR valve.