Darbeau M Z, Lutz R J, Collins W E
Department of Chemical Engineering, Howard University, Washington, DC 20059, USA.
ASAIO J. 2000 Nov-Dec;46(6):669-78. doi: 10.1097/00002480-200011000-00006.
Study of arterial blood flow dynamics improves our understanding of the development of cardiovascular diseases such as atherosclerosis. The transport and accumulation of macromolecules in the arterial wall can be influenced by local fluid mechanics. We used numeric simulations to investigate such transport in a T-junction model. Presumably an in vitro experiment would consist of gel segments inserted in the walls of a mechanical flow T-junction model near branch points where separation and recirculation zones are expected. The transport of low density lipoprotein (LDL) was investigated theoretically at these sites in a two dimensional numeric T-branch model. In the numeric model, the hydraulic conductivity of the porous gel wall segments was varied for a fixed species diffusivity to provide simulations with wall transmural Peclet numbers ranging from 0.3 to 30. Steady state flow patterns in the lumen of the two dimensional T-branch were simulated at Reynolds numbers of 250 and 500, using the software package FIDAP 7.61 to implement the finite element method. The simulations demonstrated that wall Peclet numbers greater than 1.0 were needed to achieve species concentration gradients within the wall that varied in the axial direction, thereby reflecting the influence of disturbed flow and pressure patterns in the lumen. As expected, the transmural concentration gradients were steeper when convection predominated. Blood flow in the lumen can influence the distribution of macromolecules in the arterial wall and needs to be investigated for the relevance to atherosclerosis.
对动脉血流动力学的研究有助于我们更好地理解心血管疾病（如动脉粥样硬化）的发展。大分子在动脉壁中的运输和积累会受到局部流体力学的影响。我们使用数值模拟来研究T型分支模型中的这种运输。据推测，体外实验可能包括在机械流动T型分支模型壁上靠近分支点处插入凝胶段，在这些分支点处预计会出现分离和回流区域。在二维数值T型分支模型中，对这些部位低密度脂蛋白（LDL）的运输进行了理论研究。在数值模型中，对于固定的物种扩散率，改变多孔凝胶壁段的水力传导率，以提供壁跨膜佩克莱数范围从0.3到30的模拟。使用软件包FIDAP 7.61实施有限元方法，在雷诺数为250和500的情况下，模拟了二维T型分支管腔内的稳态流动模式。模拟结果表明，需要壁佩克莱数大于1.0才能在壁内实现沿轴向变化的物种浓度梯度，从而反映管腔内紊乱流动和压力模式的影响。正如预期的那样，当对流占主导时，跨壁浓度梯度更陡。管腔内的血流会影响大分子在动脉壁中的分布，需要对其与动脉粥样硬化的相关性进行研究。
