DRBEM solution to ferrofluid flow and heat transfer in semi annulus enclosure in the presence of magnetic field

2016-07-11
Oğlakkaya, Fatma Sidre
Bozkaya, Canan
In this work, ferrofluid flow and heat transfer in a semicircular annulus enclosure filled with Fe3O4- water nanaofluid is studied in the presence of an externally applied magnetic field. The inner and outer circular walls are maintained at constant temperature and two straight boundaries at the bottom are considered adiabatic. The governing equations which are consistent with the principles of ferrohydrodynamics (FHD) and magnetohydrodynamics (MHD) are discretized by using the dual reciprocity boundary element method (DRBEM) with constant elements. The DRBEM aims to convert the given differential equations into boundary integral equations by the use fundamental solution of Laplace equation and by treating the nonlinear terms with radial basis function approximation. The numerical results are obtained for different values of physical parameters such as Rayleigh number, Hartmann number arising from MHD and magnetic number arising from FHD to see the effect of both FHD and MHD on the flow and heat transfer. Results show that the flow is retarded with an increase in Hartmann number which results in a decrease in the strength of stream function and the core of the main vortex in streamlines moves towards the straight bottom walls. Further, secondary vortices are formed symmetrically near the vertical centerline at high magnetic numbers. The isotherms show a smooth distribution which are parallel to each other inside the annulus in the absence of FHD effect, while thermal plumes occur on the isotherm profile as the magnetic number increases. However, these plumes vanish with an increase in the Hartmann number. On the other hand, as the Rayleigh number increases, the heat transfer becomes convection dominated and as a result formation of thermal plumes is observed on the top of the inner wall.
Advances in Boundary Element & Meshless Techniques XVII-BETEQ 2016

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Citation Formats
F. S. Oğlakkaya and C. Bozkaya, “DRBEM solution to ferrofluid flow and heat transfer in semi annulus enclosure in the presence of magnetic field,” Ankara, Turkey, 2016, p. 107, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/87478.