Mixing Enhancement in 3D MHD Channel Flow by Boundary Electrical Potential Actuation
L. Luo and E. Schuster
American Control Conference
Baltimore, Maryland, USA, June 30 - July 2, 2010
Abstract
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An electrically conductive fluid flowing inside a channel is prone to
be affected by enormous magnetohydrody- namics (MHD) effects when the
fluid interacts with an imposed magnetic field. Such effects often
leads to higher pressure drop and lower heat transfer rate due to
laminarization. Active boundary control, in either open loop or
closed loop, can be used to enhance mixing and potentially increase
heat transfer rate. Open-loop controllers are in general more
sensitive to uncertainties of the system, which may result in a
poorer performance. A closed-loop controller is proposed based on the
linearized simplified magnetohydronamic (LSMHD) model. Micro pressure
sensors and electrodes are embedded into the walls for measurement
and actuation. Using the boundary vorticity flux as the input, the
proposed feedback controller regulates the boundary electric
potential at the channel walls in order to increase turbulence and
mixing. By reversing the sign of a feedback controller designed to
stabilize the LSMHD systems, a destabilizing controllers is achieved
and used to excite multiple Fourier modes in simulations. The
simulation results provided by a 3D simplified magnetohydronamic
(SMHD) simulator show that the reversed controller successfully
increases the turbulence inside an otherwise strongly stable MHD flow.