Effect Of Magnetic Field On Blood Flow And Heat Transfer Through A Stenosed Artery

Arteriosclerosis, a stenosis (constriction) in blood vessels, cause high flow velocity, shear stress and low or negative pressure at the throat of the stenosis, low shear stress, wall compression, flow separation or even vortex at the distal side of the stenosis. Researches show that the interaction of stenosis and the abnormal flow may lead to the further deterioration of stenosis.Blood behaving electric conduction and magnetization is a characteristic biomagnetic fluid. In this study, a numerical model with FSI (fluid-structure interactions) concerning the varying viscosity was introduced to obtain the main flow and heat reansfer charactersitics such as flow velocity, pressure, shear stress and heat flux for studying the effect of magnetic field on the flow and heat transfer in an elastic tube with symmetric stenosis. Results indicate that:Firstly, the influence of elastic wall on blood dynamical properties was investigated numerically. The results showed that the velocity and pressure were increased with the wall stress decreasing. Compared with the value of the rigid model, the peak flow velocity of the elastic model was 3.7% higher, the peak pressure was 9.1% higher, while the peak wall stress of wall ? = 0°and ? = 180°were 11.5% and 5.2% lower than that of the rigid model.Secondly, the non-Newtonian property of blood was investigated numerically and the results were compared with that of Newtonian fluids. It was observed that the vortex formed downstream of the stenosis for non-Newtonian fluid was smaller than the vortex for Newtonian fluid. In the case of pure hydrodynamic flow, the size of vortex for Newtonian fluid was 3 times larger than that for non-Newtonian fluid. In the case under magnetic field, the size of vortex for Newtonian fluid was 0.5 times larger than that for non-Newtonian fluid.Finally, the effect of magnetic field on the blood flow and temperature fields in the stenosed artery away from the heart was investigated numerically. For the case of a spatially varying magnetic field generated by an electric wire, the symmetry of the flow downstream of the stenosis broke and the vortex near to the magnetic source was enlarged by three times. The maximum temperature downstream of the stenosis was 0.36K lower in the most regions near to the magnetic source than the corresponding temperature in the pure hydrodynamic case. In contrast, the maximum temperature downstream of the stenosis away from the magnetic source was increased by 0.9K. The maximum temperature of wall away from the magnetic source was higher by 0.96K than that of the wall near to the magnetic source. For the case of applying a spartial varying magnetic field perpendicularly, the vortex near to the magnetic source was enlarged in the magnetic field region. The maximum temperature of wall away from the magnetic source was higher by 1.3K than that of the wall near to the magnetic source. A larger vortex arose downstream of the magnetic field, and the maximum temperature of wall away from the magnetic source was lower by 2.2K than that of the wall near to the magnetic source.