肝脏中生物流体流动的多重介质渗流模型和数值模拟

IMECH-IR > 力学所知识产出(1956-2008)

	肝脏中生物流体流动的多重介质渗流模型和数值模拟
	刘庆杰
导师	梁乃刚 ; 郭尚平
	1999
学位授予单位	中国科学院研究生院
学位授予地点	北京
学位类别	博士
学位专业	固体力学
关键词	生物渗流多重多孔介质分级多孔介质肝血窦窦周间隙毛细胆管肝脏血流动力学 Biofluid Flow In The Porous Media Multiporous Media Hierarchical Porous Media Hepatic Sinusoid Perisinusoidal Space Bile Canaliculus Hemodynamics
英文摘要	本文采用生物渗流理论，建立了肝脏内不同生物流体流动的多重介质渗流模型，采用有限元法求解这种特殊的渗流问题，根据数值计算结果揭示了肝内血液、组织液以及胆汁等的流动规律，并探讨了肝脏血流动力学的一些问题。论文将肝脏内部与生物代谢功能有关的肝血窦和窦周间隙当作两重并存的多孔介质，血液在肝血窦中，以及组织液在窦周间隙中的流动均当作渗流处理，通过Starling公式考虑了两重介质之间的流量交换，从而建立了肝血窦-窦周间隙的双重介质模型。针对肝脏胆汁分泌功能，将肝脏内密布的毛血肝管网当作多孔介质，以受静压及渗透压驱动的流体跨壁流动表示肝汁从肝细胞向毛细肝管的分泌，肝汁在毛细胆管网中的流动作为渗流处理，从而建立了肝汁分泌与输运的双重介质模型。采用有限元法求解了生物流体的双重介质渗流问题，针对非牛顿渗流和两重介质的相互作用，本文发展了一种嵌套迭代方法，即采用直接迭代求解血液在肝血窦中的非线性渗流，采用交替迭代解决双重介质渗流中由跨壁流支引起的相互流体交换，直接迭代嵌套于交替迭代中。这种算法比较有效的解决了包含非牛顿渗流的双重介质渗流问题。根据生物多孔介质中微细管系统的构筑方式以及不同微细管系统之间的联系方式，论文提出将生物多孔介质划分为分级多孔介质和多重多孔介质两种主要类型。基于多相混合物的平均化的理论，论文推导了双重多孔介质中的动量守恒方程、质量守恒方程以及相应的渗流方程，建立了双重多孔介质渗流的平均化模型。基于分级多孔介质渗流的理论，论文将脏器中的血管树按管径分为不同级别的多孔介质，各级血管中和血液流动均作为渗流处理，从而提出了计算脏器整体血流的一种渗流方法。采用这种方法，在论文提出的肝血窦 - 窦周间隙双重介质渗流流模型的基础之上，初步研究了肝脏门静脉系统的血液动力学规律。采用本文提出的肝血窦 - 窦周间隙双重介质模型和胆汁分泌 - 流动的双重介质模型，得到了血液、组织液和胆汁在肝小叶中的压力分布和速度分布，并分析了肝血窦壁的跨壁流动模式，胆汁流量的影响因素，以及窦周间隙中组织液流量与肝血窦中血液流动及肝血窦壁渗透系数等因素的关系，揭示了肝脏内血液、组织液及胆汁等生物流体流动的一般规律。; A multiporosity model for the biofluid flow in the liver was presented in this paper, the governing equations were resolved by using of the Finite Element Method, the flow feature of the blood in the sinusoid, the interstitial fluid in the perisinusoidal space and the bile in the canaliculus were investigated, and some hemodynamics problems in the liver were discussed. A double porosity model was built for the blood flow in the sinusoid and the interstitial fluid flow in the perisinusoidal space, in which the sinusoid and the perisinusoidal space were treated as two kinds of porous media in the liver, the transmural flow between this two media were considered by Starling equation, and the complexity of the fluid flow in the microvasculature and interstitial space were overcome by applying principles from porous media theory. For the process of bile secretion and transport in the liver, the secretion of the bile is modeled as transmural flow driven by the hydrostatic pressure difference and the osmotic pressure difference across the hepatocyte membrane, the bile canaliculus was treated as porous media, and the principles from double porous media theory were applied for the simulation of bile secretion and transport. The numerical simulation of the governing equations is performed by utilizing the Finite Element Method. An Embedded Iteration algorithm was developed for the Non-Newtonian fluid flow through the double porosity media, in which the embedded Direct Iteration was applied for the nonlinear flow and the Alternate Iteration was adopted for the coupling between two porous media. It is shown that this algorithm has well convergence for the Non-Newtonian fluid in the double porous media. The bioporous media is characterized into hierarchical porous media and multiple porous media according to the construction and intercommunication of the microvasculature. The conservation laws for mass and momentum and an extended Darcy equation for the double porous media have been derived by means of a formal averaging procedure in which the discrete network of microvessel was transformed into a continuum. A method of hierarchical porous media were introduced for the calculation of the total blood flow of the viscera, in which the vasculature were subdivided into various hierarchical porous media according to the diameter of the vessel, and the blood flow in the vasculature were investigated by the using of the theory of fluid flow through porous media. With this method and based on the flow pattern in a hepatic lobule obtained from the double porosity model of sinusoid and perisinusoidal space, the hemodynamics of the portal veineous system were investigated. The pressure distribution and velocity distribution of the blood, interstitial fluid and bile in the hepatic lobule were obtained based on the multi-porosity model presented this paper. The transmural flow across the sinusoid wall, the bile flow and the relationship between the interstitial fluid flow in the perisinusoidal space and the blood flow in the sinusoid were investigated, the results provide a fundamental understanding for the microcirculation in the liver.
索取号	29864
语种	中文
文献类型	学位论文
条目标识符	http://dspace.imech.ac.cn/handle/311007/23464
专题	力学所知识产出(1956-2008)
推荐引用方式 GB/T 7714	刘庆杰. 肝脏中生物流体流动的多重介质渗流模型和数值模拟[D]. 北京. 中国科学院研究生院,1999.

条目包含的文件
文件名称/大小	文献类型	版本类型	开放类型	使用许可
肝脏中生物流体流动的多重介质渗流模型和数（16294KB）			开放获取	--	请求全文