Evaluating the Effect of Magnetic Field, Impulse Flow and Gravity Acceleration on Different Femoral Bypass Angles in Order to Remove Lipid Accumulations in Atherosclerosis Disease by Simulation Method

Abstract

Aterosclerosis and obstructions especially in great and vital arteries cause blood circulation system numerous disorders. Coronary arteries, carotid and femoral as the most important arteries could be affected negatively by aterosclerosis which may result in shock or heart attack. Bypass surgical operation is a significant method to treat clogged arteries nowadays and should be designed as perfect as it would minimize flow turbulence. Numeral simulation techniques are among the most recommended methods to reach this purpose. While most of researchers considered blood as a Newtonian fluid and none has studied magnetic field effect on bypass, we aimed to evaluate blood flow as a non-Newtonian fluid in presence of magnetic field and gravity acceleration in different bypass angels. A model of three-dimensional femoral artery with bypass and rigid wall was assumed. Percentages of blockage was defined by following formula; [(A i -A s )/A i ] in which A i was non-blockage area, and A s was the artery's narrowest part area. Desired geometry was modeled by SolidWorks software then networked in Gambit software. There were three different equations applied including: Equation of the artery in the blockage area, sinusoidal relationship based on Reynolds number and fluid equation of continuity and momentum. Magnetic force of blood flow acted as a resistant tensional force and in presence of magnetic field normal blood flow was observed and subsequently outward viscosity was increased. Magnetic field also caused thickening boundary layer and as velocity gradient increased close to the walls shear stress enhanced. When magnetic field increased and Hartmann number enhanced subsequently there was no observation of negative shear stress. In the bypass entrance a returned flow occurred. By developing the Hartmann number vortex power decreased so that in 10 and 20 Hartmann returned flow was vanished completely. All of hemodynamic parameters and environmental factors that affect them are necessary to improve the efficiency of bypass surgical operations. If the three-dimensional modeling approaches maximally match with the reality they could help the specialists to choose the best location and angel of the bypass and improve the achievement probability significantly.