Multi-Physics Analysis of Electromagnetic Valves Based on Volumetric Energy Conversion

Ferrofluids have been used in development of active dampers due to their controllable magnetic and mechanical properties. However, design and control of these actuators are far from exhausted. The fluid nature of volumetric energy converters using ferrofluids provides additional degrees of freedom in design and operation, yet numerical analysis of such devices includes inherent multi-physics computations that can be complex. Control of a three-dimensional motion can result in substantial reduction in cost and design of electro mechanic actuators. In this paper, a ferrofluid valve is proposed. Ferrofluid is used as an actuator to open and close water flow through a channel. By changing the distribution of ferrofluid, the cross-section area of the open passage in the flow channel is controlled. To reduce the deterioration of ferrofluid in the presence of water, the ferrofluid and the controlled flow are separated by a nitrile rubber film. By varying the strength of magnetic field, the ferrofluid valve can be fully closed and opened. A multi-physics numerical simulation of the valve has been carried out to determine the opening and closing time of the valve, maximum cut off flow rate, pressure drop and resolution. The valve closing time is simulated to be 125ms in a 4 inches by 2 inches prototype. This prototype has been built to validate the simulation results.