11022

10153

كارشناسي ارشد

مهندسي شيمي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مهندسي شيمي

1394

دوازده، 89ص.: مصور

محسن نصراصفهاني

مسعود حق شناس فرد

ابراهيم شيراني، ارجمند مهرباني

1394/12/10

مهندسي شيمي

ID10153

Investigation of The Effects of Rheological Models in CFD Analysis of Blood Flow in Cerebral Aneurysms Shima jafarian s jafarian@ce iut ac ir Date of Submission 2016 1 16 Department of chemical engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiMohsen Nasr Esfahany mnasr@cc iut ac irMasoud Haghshenasfard haghshenas@cc iut ac irAbstractHemodynamic factors play an important role in the initiation progression and rupturing of intracranialaneurysms In this study Computational Fluid Dynamics CFD is used to investigate the effects ofblood rheology models Newtonian and Casson on the hemodynamic parameters The content of thisresearch is divided into two parts and qualitative and quantitative results are presented In the firstpart effects of variations of the blood flow on aneurysmal hemodynamic in a ruptured internal carotidartery aneurysm are discussed for Newtonian and Casson model CFD simulation was carried out forthree situations normal and 20 increase and decrease in the inflow Qualitative observationsindicate that 1 increase in the inflow increases the difference between the Newtonian WSS WallShear Stress and Casson WSS Quantitativ observations indicate that WSS is more sensitive to therheological models used for predicting flow behavior in aneurysms than velocity In the second part CFD simulations were carried out for ten saccular aneurysms to investigate the differences betweenthe two models in different conditions Qualitative observations indicate that 1 WSS OscillatoryShear Index OSI velocity distribution and flow pattern have similar characteristics for bothrheology models 2 Newtonian model overestimates the velocity in the most areas near the wall ofaneurysm sac and parent vessel 3 There is no preference in using Casson on Newtonian models forregions of low WSS The same fact was observed for OSI and velocity Quantitative observationsindicate that 1 Newtonian model overestimates the space average velocity at peak systole in theaneurysm sac about 12 5 2 The difference between Casson and Newtonian WSS predictionsincreases by decreasing the WSS values and increasing OSI over aneurysm wall So while studyingnear wall regions with certain biological mechanisms e g thrombogensis in mind it is important tochoose Casson model that appropriately model the shear thining nature of blood Otherewise it ispreferred choosing Newtonian model because of its ease of application Keyword Interacranial aneurysm Non Newtonian rheology Computational fluid dynamics CFD Blood flow

محسن نصراصفهاني

مسعود حق شناس فرد

ابراهيم شيراني، ارجمند مهرباني