Magneto-hydrodynamic coupling modeling of a pinch-mode magnetorheological valve with multiple non-magnetic edges

The magnetorheological effect of the pinch-mode magnetorheological valve (pinch-mode MR valve) depends on the complex coupling between nonlinear gradient magnetic fields and magnetorheological fluids, especially for the configuration with multiple non-magnetic edges, which is rarely investigated. In this study, a magneto-hydrodynamic coupling model of pinch-mode MR valve with multiple non-magnetic edges is established to capture the interactions between non-uniform magnetic fields and hydrodynamic behavior, firstly. Secondly, the experimental data of pressure drop between the inlet and outlet is utilized to verify the model accuracy. The comparison results show that the established model, considering the wall movement to describe the flow separation of MR flow dynamics caused by the pinch effect, can describe the variable properties of the viscous damping and pre-yield damping with different magnetic fields and fluid flow with relative agreement. Finally, through the parameter sensitivity analysis based on the established model, it is shown that the pinch-mode MR valve with about 6.5 mm channel diameter can provide a better performance in absolute pressure drop adjustment range and pinch effect. Besides, the width of the coil bracket can be utmost designed without the magnetic saturation in steel yoke, improving the damping properties of the pinch-mode MR valve.