人胸主动脉血液脉动流的三维数值分析

目的:探讨在正常生理脉动流条件下人体胸主动脉内血液流动速度、血管壁面压力和壁面剪应力的分布,为阐明主动脉夹层的发病机制提供理论依据.方法:运用计算流体力学方法和血流动力学的基本原理,对正常人的胸主动脉内血液脉动流进行三维数值模拟.结果:计算获得了正常人的胸主动脉内血液流动在心动周期不同时刻的壁面压力、壁面剪应力、速度和流线分布.收缩期的血管壁面压力比舒张期的血管壁面压力具有更大的量值和变化幅度;在整个收缩期过程中,外侧壁的压力明显地高于内侧壁的压力;主动脉弓和降主动脉的交界处存在明显的压力降.主动脉弓外侧壁的壁面剪应力比主动脉弓内侧壁的壁面剪应力要小很多;主动脉弓内侧壁的壁面剪应力比主动脉弓外侧壁的壁面剪应力具有更大的量值和变化幅度,呈现出周期性的交变应力.结论:血管壁面压力可能与主动脉夹层的发生有关.

Three-dimensional simulation of pulsatile blood flow in human thoracic aorta

Objective:To study the distributions of velocity, wall pressure and wall shear stress of blood flow in the human thoracic aorta under normal physiological pulsatile flow conditions,so as to provide a theoretical foundation for elucidating the pathogenesis of aortic dissection.Methods: By virtue of the Computational Fluid Dynamics and the fundamentals of hemodynamics,the authors obtained the numerical simulations and flow visualizations of pulsating blood flow in the human thoracic aorta.Results: The distributions of velocity,wall pressure,wall shear stress and path line of the blood flow in the thoracic aorta were calculated with a function of time in the cardiac circle.The systoltic wall pressure and its dp/dt were higher than diastolic wall pressure and its dp/dt.The pressure of lateral wall was higher than the pressure of medial wall during systole.A distinct depressed pressure was found located at the intersection between aortic arch and descending aorta.Shear stress of wall of lateral aortic arch was less than that of medial wall of aortic arch and the shear stress change in medial wall of aortic arch was greater than that in the lateral aortic wall.The shear stress was in a cyclic and alternative manner.Conclusion: The findings suggest that the wall pressure may be related to the development of aortic dissection.