离心式心脏泵流场数值计算与分析

发布时间：2018-06-12 18:23

本文选题：数值模拟 + CFD　；参考：《兰州理工大学》2011年硕士论文

【摘要】：CFD技术是一种强大的数值模拟工具,本课题利用CFD软件对采用一元理论的方法所设计的无回流区和有回流区两种离心式心脏泵模型进行数值模拟,较好地分析和认识了人工心脏泵叶轮内部流场的分布,揭示了叶轮内部流动的特殊规律和流动机理。通过数值模拟得到了心脏泵流道内的切应力分布云图,速度分布云图以及压强分布云图,分析对比了两种模型对血栓和溶血的影响,为人工心脏泵在提高抗血栓和溶血性能方面打下良好的基础。为此,本课题进行了如下研究: 1.通过综合分析国内人工心脏泵的研究现状,以N-S方程为基础,阐述了CFD的基本理论,分析了CFD模拟过程中所用到的模型及数值计算方法。 2.采用一元理论的设计方法对离心式心脏泵进行了水力设计,利用Pro/E软件绘制水力设计的平面图,并且建立了三维实体模型。将三维实体模型导入网格划分软件ICEM中生成流动区域,再利用四面体非结构化网格对流动区域进行网格划分,并简单阐述了网格对计算解的影响。 3.将得到的msh文件导入流体数值仿真软件FLUENT中,设置流体的参数和边界条件,采用RNG k-ε湍流模型和压力耦合的SIMPLEC算法求解方程,最终实现了人工心脏泵流场的数值模拟。 4.在相同的边界条件下,得到的模拟结果显示:心脏泵内的绝对速度场与压力场的分布与理论研究相一致,并且有回流区模型的绝对速度场与压力场的分布情况要好于无回流区模型; 5.两种心脏泵的叶片工作面中部,均出现流动涡流现象,但是有回流区模型的湍流区域小于无回流区模型的湍流区域,也就是有回流区心脏泵模型的流动效果要好一些。 6.从两种心脏泵的切应力分布图可以看出,有回流区离心式心脏泵内部的最大切应力要比无回流区离心式心脏泵小,且切应力高于产生溶血的临界切应力(150Pa)的区域要比无回流区离心式心脏泵的区域小。因此对血细胞的破坏更小,进一步说明有回流区离心式心脏泵模型更符合血液动力学的要求。
[Abstract]:CFD technology is a powerful numerical simulation tool. In this paper, we use CFD software to simulate two kinds of centrifugal heart pump models without reflux region and reflux zone, which are designed by using the method of univariate theory. The distribution of flow field in the impeller of artificial heart pump is analyzed and understood, and the special law and mechanism of flow inside the impeller are revealed. By numerical simulation, the distribution of shear stress, velocity and pressure in the flow channel of the heart pump were obtained. The effects of the two models on thrombus and hemolysis were analyzed and compared. For artificial heart pump in improving the anti-thrombotic and hemolytic performance lay a good foundation. For this reason, this subject has carried on the following research: 1. Based on N-S equation, the basic theory of CFD is expounded, and the models and numerical methods used in CFD simulation are analyzed. 2. The hydraulic design of centrifugal heart pump is carried out by using the method of univariate theory. The plane diagram of hydraulic design is drawn by using Prop / E software, and the three-dimensional solid model is established. The 3D solid model is introduced into the meshing software ICEM to generate the flow area, and then the tetrahedron unstructured mesh is used to mesh the flow area, and the influence of the mesh on the computational solution is briefly described. The msh file is imported into the fluid numerical simulation software fluent, the parameters and boundary conditions of the fluid are set up, and the equations are solved by using the RNG k- 蔚 turbulence model and the coupled SIMPLEC algorithm. Finally, the numerical simulation of flow field of artificial heart pump is realized. 4. Under the same boundary condition, the simulation results show that the distribution of the absolute velocity field and pressure field in the heart pump is consistent with the theoretical study. And the distribution of the absolute velocity field and pressure field of the model with reflux region is better than that of the model without reflux region. In the middle of the blade face of the two kinds of heart pumps, the phenomenon of flow eddy current appears, but the turbulent region with reflux zone model is smaller than that with no return zone model. The flow effect of the heart pump model with reflux zone is better. 6. 6. It can be seen from the shear stress distribution of the two kinds of pump that the maximum shear stress in the centrifugal heart pump with reflux zone is smaller than that in the non-reflux zone centrifugal heart pump. The region with shear stress higher than the critical shear stress of hemolysis (150 Pa) is smaller than that of centrifugal pump without reflux. Therefore, the damage to blood cells is less, which further indicates that the model of centrifugal heart pump with reflux zone meets the requirement of hemodynamics.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH311

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