Unsteady laminar flow analysis of ER valve systems: Modeling and simulation

Abstract

This paper proposes a new method to model electrorheological valve systems based on the unsteady flow analysis. After describing the mechanism and operational principle of the ER valve, the unsteady flow in the valve is identified. A method to model this unsteady flow is developed based on the assumptions that the ER fluid follows Bingham behavior and the pressure drop of the unsteady flow results from the independent pressure drops due to the yield stress, inertia and fluid viscosity. The dynamic model of the valve is then derived based on the unsteady flow analysis. The time response of ER effect is also considered in the dynamic model. Using the proposed model, the performance of the ER valve is predicted and validated by comparing with experimental results. In addition, the flow rate predicted by the unsteady flow model is compared with that by the steady flow model.