Velocity and temperature maldistribution due to the magnetic field influence

The elements that possess the ability of changing the flow structure (neckings, nozzles, valves, elbows) can be found in numerous industrial and medical applications. This ability leads to the velocity and temperature fields modification and can be a reason of negative effects like pressure loss. These negative effects can be reduced by the usage of magnetic field. Magnetic control of weakly magnetic fluids’ velocity and temperature distributions is well known. Presented paper considers the numerical analysis of velocity and temperature maldistribution due to the influence of strong magnetic field. The analysis was carried out for three-dimensional circular duct with simplified stenosis (narrowing of the blood vessels), which took form of confusor-diffuser section of the pipe. The system included duct and the magnetic coil that was oriented perpendicularly to the flow axis and placed in between confusor and diffuser. The wall of the stenosis was divided into subzones partially heated in order to control the velocity and temperature fields. Biot-Savart’s law was applied to calculate the distribution of the magnetic field, which was then used to obtain the magnetic force distribution and added to principle of conservation of momentum equations as the external body force. Commercially available software Ansys Fluent 13 was chosen to conduct the numerical analysis, however special user-defined modulus to calculate the distribution of magnetic force was prepared and implemented in it. The results pointed out that the usage of magnetic field might provide a significant change in both velocity and temperature distribution, especially for low Reynolds number flows.

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1. Bednarz T., Fornalik E., Tagawa T., Ozoe H., Szmyd J.S.: Experimental and numerical analyses of magnetic convection of paramagnetic fluid in a cube heated and cooled from opposing verticals walls, Int. J. Thermal Sci., 44 (2005) 933-943.
2. Chakravarty S., Datta A., Mandal P.K.: Analysis of nonlinear blood flow in a stenosed flexible artery, Int. J. Eng. Sci., 33 (1995) 1821-1837.
3. Filar P.: Convection of paramagnetic fluid in a cylindrical enclosure under a strong magnetic field, Ph.D. Thesis, Kyushu University 2004.
4. Jackson J.D.: Classical Electrodynamics, John Wiley & Sons, Inc., New York 1998.
5. Kenjereš S.: Numerical analysis of blood flow in realistic arteries subjected to strong non-uniform magnetic fields, Int. J. Heat Fluid Flow, 29 (2008) 752-764.
6. Kenjereš S. and Righolt B.W.: Simulation of magnetic capturing of drug carriers in the brain vascular system, Int. J. Heat Fluid Flow, 35 (2012) 68-75.
7. Misra J.C. and Shit G.C.: Blood flow through arteries in a pathological state: A theoretical study, Int. J. Eng. Sci., 44 (2006) 662-671.
8. Ozoe H.: Magnetic Convection, Imperial College Press, London 2005.
9. Wróbel W., Fornalik-Wajs E., Szmyd J.S.: Experimental and numerical analysis of thermo-magnetic convection in a vertical annular enclosure, Int. J. Heat Fluid Flow, 31 (2010) 1019-1031.