Active Flow Control of the Magnetohydrodynamic Flow in an Annular Linear Induction Pump by Modifying the Driving Electromagnetic Field

The strong coupling between fluid and electromagnetic field in the annular linear induction pump (ALIP) can gradually amplify small disturbance in the fluid field into large-scale vortices. The appearance of the vortices seriously affects the efficiency and reliability of the pump. An active flow control method based on the modification of the driving electromagnetic field is proposed to improve the flow stability. A simplified numerical model of the ALIP is established to simulate the three-dimensional flow in the annular flow channel, and the internal electromagnetic field is modified by using the modulated surface current. The influences of the active flow control method on the flow behavior, pressure pulsation, and energy conversion are, respectively, investigated based on the simulation results. The results show that the modulated surface current can accelerate the vortical evolution. The size and strength of the vortices are suppressed in the modified electromagnetic field. The pressure pulsation low frequency at the ALIP’s outlet is significantly reduced when the modulated surface current density reaches a certain level. The surges in the processes of energy conversion become more gentle within the control method, and the overall energy efficiency is slightly reduced even at the highest modulated surface current density.