Rotating electromagnetohydrodynamic flow of power-law fluids through a microparallel channel
2017
Xie, Zhi-Yong | Jian, Yong-Jun
In this study, rotating electromagnetohydrodynamic (EMHD) flow of power-law fluid through a narrow microchannel is investigated. The flow is actuated by the Coriolis force raised from the rotation of the microchannel and the Lorentz force induced by the interaction between electric and magnetic fields. The modified Navier-Stokes equations in the rotating frame are discretized by the finite difference method and solved through Crank-Nicolson implicit scheme under the appropriate initial and boundary conditions. Results of the present analysis are compared with existing literature for special case when the behavior index n of power-law fluid is equal to unit (Newtonian fluid). Very well agreements are obtained and the validity of the present numerical method is confirmed. The influences of the fluid behavior index n, the Hartmann number Ha and rotating Reynolds number ReΩ on the EMHD velocity distributions are discussed. The results show the velocity of the power-law fluid depends strongly on these flow parameters. Due to the existence of the uniform electric and magnetic fields, the critical Hartmann number can also be obtained for the power-law fluid. In addition, for the small Ha, a depression only appears in mainflow direction at the central part of the microchannel and the dilatant fluid (n>1) is easily affected by the rotation effect comparing to the pseudoplastic fluid (n<1). Regarding the evolution of centerline velocity of the power-law fluids with ReΩ, an auspicious phenomenon is that there exists a cross-over point for different values of the behavior index n. The present results can be utilized as an initial blue-print for the developing exquisite and efficient electromagnetic devices for applications involving flow control or species separation.
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