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1、Altair 2013 技术大会论文集 -1- 人工心脏的设计与模拟人工心脏的设计与模拟 Design and Simulation of Artificial Heart 梅琼风1 谢叻1 范慧敏2 于沪平2 叶亮2 贾敬华1 马智慧1 （1 上海交通大学材料科学与工程学院 上海 200030 . 2 同济大学附属东方医院 上海 200120） 摘摘 要：要：设计了四种不同结构的人工心脏模型，采用 Altair 公司的 HyperMesh 软件完成高质量的网格划分。通过每个模型的关键点 P 并且平行于三个基准面得到三个截面，模拟得到每种方案的三个截面上的切向速度分布。比较不同设计方案的最大切
2、向速度，确定最优设计方案。 关键词：关键词：人工心脏 CFD HyperMesh 切向速度 Abstract: Four kinds of artificial hearts have been designed. Meshes of high quality have been accomplished by using Altairs HyperMesh software. The maximum tangent velocities of three sections have been attained. The sections are parallel with three dat
3、um plane and through the special P point. The maximum tangent velocities of different designs have been compared. And afterwards, the optimum design has been decided. Key words: Artificial Heart , CFD , HyperMesh , Tangent velocity 1 Introduction The shape of artificial heart is important for flow o
4、f blood. Kaufman1 presents a methodology of a fully coupled three-dimensional time-dependent Fluid Structure Interaction (FSI) simulation of the TAH using a commercial partitioned block-GaussSeidel coupling package. A.C. Benim 2 considers mobilization of arteriosclerotic plaques during simulation of
5、 extracorporeal circulation; An arbitrary Lagrangian-Eulerian(ALE) finite element method with automatic mesh-updating is formulated by Q. Zhang 3. Kim, S.H 4 simulates a two-dimensional model for the total artificial heart by as a steady laminar and turbulent flow. The simulation of artificial heart
6、 is Fluid Structure Interaction (FSI) simulation. The deformation of the membrane in artificial heart is large in structure analysis; the material model of membrane is super-elastic. So it is difficult to simulate the 3-D model. This paper adopted a simple CFD approach, using an effective equation t
7、o assess the fluxion of blood. 2 Designs of artificial heart Four kinds of artificial heart have been designed on CAD software. One of them is showed as Fig1.In order to compare the flux capability of four designs, the simulation of CFD must be finished. The structure of artificial heart is composed
8、 of two cavities. One cavity is for air, the other cavity is for blood. There is a membrane between blood cavity and air cavity. Show as Fig2, bottom Cavity is blood cavity, Upper cavity is air cavity. In blood cavity there are two ends. One is for inlet of blood; the other is for outlet of blood. A
9、ir cavity has only one pass. The membrane has been pulled down when air flow in air cavity by this pass. When the membrane have been pulled down, the blood in blood cavity has been pulled out through the outlet. When the membrane has been pulled up, the Altair 2013 技术大会论文集 -2- blood has been sucked
10、in blood cavity through the inlet. The inlet and outlet of blood cavity is one- directional. In order to attain the flux information, three sections have been defined. At first, a special point P has been defined. P is the center of a circle, which is through three points. The first point is the cen
11、ter of section which is perpendicularity to the pass of air cavity and near the air cavity. The second point is the center of inlet in blood cavity. The third point is the center of outlet in blood cavity. The three sections named Px,Py,Pz are through the special P pint and perpendicular to coordina
12、te x,y,z directions. For each design three sections have been attained. Fig 1 Model I Fig2 Mesh of Model 1 on HyperMesh Fig3 Section of Mesh on HyperMesh Fig 4 velocity contour 3 Boundary Conditions It is difficult to simulate this kind of fluent structure interaction because the membrane material m
13、odel is too complex, and its strain is too large. So simplification has been adopted. We suppose that the membrane is position on the upper level. The blood flow in through inlet, and flow out through outlet. The velocity of blood inlet is 5m/s, the pressure of blood outlet is 0Pa. 4 Results of CFD
14、Simulation Three section Px,Py,Pz is perpendicularity to each other and through the center of blood cavity. So its velocity contour can represent the fluxion of whole cavity. In the following only three section Px results for design 1 has been showed. Altair 2013 技术大会论文集 -3- Fig5 tangent velocity co
15、ntour Fig6 velocity vector 5 Analysis of result Vector velocity has three components: tangent velocity Vt, radius velocity Vr, axial velocity Va. Blood flow easily along its forward directions when the ratio of axial velocity in whole velocity is big. The ratio of tangent velocity in whole velocity
16、is bigger, that means the blood cell have been cut more easily. So Vt/V,Va/V can be used to evaluate the fluxion of blood. Datas of Va/V and Vt/V shows as table 1. Vais the average value of Va/V ,Vt is the average of Vt/V,Sis a parameter used to assess the fluxion and damage of cells. Sis smaller, the cells in bl
