CFD Simulation for the Extraction of Blood Clot in the Middle Cerebral Artery Using GP2 Device through a 3 phase flow Model

Stroke has been considered one of the most fatal disease identified by mankind, killing at least five million people per year. In order to combat this disease, several mitigation measures have been discovered through research, namely thrombolysis drug through consumption or mechanical devices through surgery such as balloon angioplasty, embolectomy and Mechanical Embolus Removal in Cerebral Ischemia (MERCI). Each of these methods have their disadvantages, more prevalently on heavy requirements and potential damage to the artery. However, a proposed device named Gillian-Pearce (GP) device was introduced which claims having lower surgical risks and damage to the patient’s artery, through a simple concept of vacuum suction. The device remains untested on a real environment and thus, CFD analysis is done to enable simulation of the device in which it is more cost saving, safe and risk free.
The GP device is designed, modelled and simulated through CFD using ANSYS Design Modeller and FLUENT, using a three phase Volume of Fluid model i.e. air, blood and blood clot. Grid sensitivity study is also done to determine the best meshing size for the model of which the need to balance between the size of mesh and to minimise computational time. Additionally, comparison of two and three phase flow model is done in which to study the difference of extraction rate when additional phase is introduced, i.e. air, into the system. Furthermore, a proposed new GP2 device with different structural tubes is designed that is able to extract blood clot much faster compared to the old previous model.
It was found out that the best meshing size, i.e. between 0.25 mm, 0.20 mm and 0.15 mm, is 0.20 mm which is both fine enough for accuracy of results and short enough for computational time. Next, it was found out that the additional phase into the system will add to more lag time for the extraction process due to the presence of additional viscous fluid, of at least 12% increase in time of removal as compared to the two phase model. Finally, the newly proposed GP2 device is able to remove the blood clot at a rate of 9% much faster as compared to the old GP2 device due to having a larger area of suction for better mass transfer of the blood clot.