Non-Newtonian Computational Fluid Dynamics (CFD) Modeling on Blood Clot Extraction

Several diseases such as atherosclerosis, strokes and heart attacks cases are alarming. One of the major contributors for these diseases is formation of thrombus in blood artery. Medical advancement has seen various efforts to overcome the cause, one of the method used is by removing the blood clot with GP device whereby the clot is removed without damaging the arterial wall. Since it requires the knowledge of the fluid behavior at certain parameters (viscosity), which is certainly difficult to determine in real time. Hence, computational fluid dynamics (CFD) comes in handy to solve the problem. A simple, but powerful method is the Volume of Fluid (VOF), is a sub of computational fluid dynamics. This VOF model functions as tracking and locating the free surface which belongs to the class of Eulerian. It is a two-phase problem consisting of blood and blood clot.
Blood is often assumed to be Newtonian fluid for modeling purposes. In reality, blood viscosity varies upon certain factors and individuals, which means it exhibits non-Newtonian fluid properties. Since blood exhibits non-Newtonian behavior, Power Law is used to define the viscosity of the blood flow and blood clot. This leads to a blood clotting modeling by using the Ansys Fluent. Several equations are used to set the boundary conditions and parameters such as Navier-Stokes equation. During the grid size selection, the finer grids are used to result in higher accuracy calculation which is at 0.1mm grid size.
Next, the GP device model will be analyzed by comparing the Newtonian fluid and non-Newtonian fluid at pressures of 40kPa, 50kPa and 60kPa. Theoretically, blood is a shear thinning fluid which means its viscosity decreases as the shear stress increases which mean it will result in faster blood clot extraction time. Based on the results obtained, it is parallel to the theoretical study whereby the non-Newtonian blood clot extraction time decreases as the pressure of suction increases. In addition to that, the clot extraction time for non-Newtonian model is relatively faster compared to Newtonian models at 40 kPa, 50 kPa and 60 kPa.