Shim Eun Bo, Yeo Jong Young, Ko Hyung Jong, Youn Chan Hyun, Lee Young Ro, Park Chan Young, Min Byoung Goo, Sun Kyung
Department of Mechanical Engineering, Kumoh National University of Technology, Kyungbuk, Kumi, South Korea.
Artif Organs. 2003 Jan;27(1):49-60. doi: 10.1046/j.1525-1594.2003.07180.x.
Flow in the blood sac of the Korean artificial heart is numerically simulated by finite element method. Fluid-structure interaction algorithm is employed to compute the three-dimensional blood flow interacting with the sac material. For verification of the numerical method of fluid-structure interaction, two-dimensional flow in a collapsible channel with initial tension is simulated and the results are compared with numerical solutions from the literature. Incompressible viscous flow and linear elastic solid are assumed for the blood and the sac material in the device, respectively. The motion of the actuator is simplified by a time-varying pressure boundary condition imposed on the outer surface of the sac. Numerical solutions on the unsteady three-dimensional blood flow in the sac are provided for the cactus-type model in this study. During systole, the inlet is closed and the blood sac is squeezed by the action of the prescribed pressure on the surface. During diastole, the sac is filled with the blood coming from the inlet while the outlet is closed. A strong flow to the outlet and a stagnated flow near the inlet are observed during systole. Shear stress distribution is also delineated to assess the possibility of thrombus formation. We also simulate numerically the hemodynamics of "the reversed model" where the inlet and outlet are reversed for surgical convenience. It is observed that a recirculating flow was generated near the inner corner of the sac in the reversed model. To assess the material strength of the sac, the shear stress distribution in the solid material is also presented.
采用有限元方法对韩国人造心脏血囊内的血流进行数值模拟。运用流固耦合算法计算与血囊材料相互作用的三维血流。为验证流固耦合数值方法，对具有初始张力的可塌陷通道内的二维流动进行模拟，并将结果与文献中的数值解进行比较。分别假设装置中的血液为不可压缩粘性流体，血囊材料为线性弹性固体。通过施加在血囊外表面的时变压力边界条件简化驱动器的运动。本研究给出了仙人掌型模型血囊内非定常三维血流的数值解。在收缩期，入口关闭，血囊在表面规定压力的作用下被挤压。在舒张期，血囊在出口关闭时被来自入口的血液充满。收缩期观察到流向出口的强流和入口附近的滞流。还描绘了剪应力分布以评估血栓形成的可能性。为便于手术，我们还对“反向模型”（入口和出口颠倒）的血流动力学进行了数值模拟。观察到在反向模型中血囊内角附近产生了回流。为评估血囊的材料强度，还给出了固体材料中的剪应力分布。
