Conduit flow control through magnetorheology

In this paper it is addressed the problem of flow stability in conduits when an essentially steady flow is perturbed by undesirable fluctuations of the pressure gradient. This problem may arise when working conditions in conduit systems induce sporadic or permanent oscillations of the pressure at the end of some conduits. In cases where the flow occurs in closed circuits and it is important to reduce or eliminate flow fluctuations, it is possible to impose flow control by making use of the magnetorheological properties of some fluids. An analytical model is presented in which the working fluid is assumed to be affected by a magnetic field whose strength is proportional to the instantaneous rate of flow. In this way, it is shown that oscillatory perturbations of an otherwise constant pressure gradient can be damped away through the synchronized oscillations of the yield stress generated in the fluid by the magnetic field. The paper includes the solution of the analytical model and several examples of applications.