基于流固耦合计算机流体力学模拟分析人体主动脉弓内血液流动

Analysis of blood flow in human aortic arch by fluid-structure interaction coupled computational fluid dynamics simulation

目的比较分析应用弹性血管壁的流固耦合计算流体力学(CFD)方法和刚性血管壁的CFD方法模拟获得的正常主动脉弓内血流动力学参数,同时比较两种方法的优劣,为深入研究血液流动状态与动脉疾病的关系提供帮助。方法取46岁男性,胸主动脉正常CT图像,格式为Dicom,层间距为0.5mm,每片图像的平面分辨率为512×512,像素大小为0.5mm。应用医学图像后处理软件,对通过临床获得正常人体主动脉CT二维医学图像数据进行重构,得到主动脉血流及血管壁的三维立体模型并应用于模拟计算。结果在设定边界条件和初始条件的基础上,经多次迭代耦合计算,获得血管壁形变、等效应力、血流速度、壁面振荡切应力等相关血流动力学参数。结论在心动周期内弹性血管壁的主动脉内血流情况较刚性血管壁主动脉内血流情况更为复杂,管壁等效压力变化较大,血管壁的振荡切应力更高,表明弹性血管壁的流固耦合的CFD模拟更能体现真实主动脉内复杂血流情况,为深入研究血流动力学与心脑血管疾病的关系提供了一定的技术支持。

Objective To analyze the hemodynamic parameters of normal aortic arch obtained by fluid-structure interaction（FSI） based computational fluid dynamic（CFD） simulation of blood flow in elastic vessel wall and rigid vessel wall based on CT image guided three-dimensional reconstruction,and compare the difference between the two methods,with the purpose to provide assistance for further studying relationship between blood flow status and arterial diseases.Methods The subject was male,46-year-old,with normal aortic arch.The CT image was of Dicom format,with layer distance of 0.5 mm,plane resolution of 512 × 512 and pixel size of 0.5 mm.The medical image post-processing software was applied to reconstruct the two-dimensional CT image to obtain the three-dimensional model for FSI and CFD simulation.Results After several interaction coupling calculation under pre-set boundary condition and initial condition,several hemodynamic parameters were obtained,which included vessel wall deformation,equivalent stress,blood flow velocity,wall oscillatory shear index and other related hemodynamic parameters.Conclusion Within the cardiac cycle,blood flow in the elastic vessel wall model is more complex than the rigid vessel wall model,with larger equivalent stress changes and higher vessel wall oscillation shear stress.It is demonstrated that CFD simulation of fluid-structure interaction of elastic vessel wall better reflects the natural aortic complex blood flow,and provides technical support for future study on the relationship of hemodynamic with cardiovascular and cerebrovascular diseases.