HEAT TRANSFER ENHANCEMENT OF MHD FLOW BY A ROW OF MAGNETIC OBSTACLES

The appearance of vortex-shedding phenomena in electrically conducting viscous fluid flow past a magnetic obstacle is similar to the flow behind solid obstacles. This feature can be used for efficient enhancement of the wall-heat transfer, for better mixing of passive scalars or for the flow control of electrically conductive fluid. In the present work, the fluid flow and heat transfer characteristics around a row of magnetic obstacles are investigated numerically. The heat transfer behaviors, flow resistance, and vortex structures of the magnetic obstacles are presented, and the influence of dimensionless parameters, such as Reynolds numbers and interaction parameters, are also discussed. It is shown that the downstream cross-stream mixing induced by the magnetic obstacle wakes can enhance the wall heat transfer, so that the maximum value of percentage heat transfer increment (HI) is equal to about 69.5%. Moreover, the global thermal performance factor is increasingly dependent on the interaction parameter for a constant Reynolds number.