PDF(Pubmed)
Abstract：
This study aimed to reduce the risk of graft occlusion by evaluating the two-phase flow of blood and LDL nanoparticles in coronary artery grafts. The study considered blood as an incompressible Newtonian fluid, with the addition of LDL nanoparticles, and the artery wall as a porous medium. Two scenarios were compared, with constant inlet velocity (CIV) and other with pulsatile inlet velocity (PIV), with LDL nanoparticles experiencing drag, wall-induced lift, and induced Saffman lift forces, or drag force only. The study also evaluated the concentration polarization of LDLs (CP of LDLs) near the walls, by considering the artery wall with and without permeation. To model LDL nanoparticles, the study randomly injected 100, 500, and 1000 nanoparticles in three release states at each time step, using different geometries. Numerical simulations were performed using COMSOL software, and the results were presented as relative collision of nanoparticles to the walls in tables, diagrams, and shear stress contours. The study found that a graft implantation angle of 15° had the most desirable conditions compared to larger angles, in terms of nanoparticle collision with surfaces and occlusion. The nanoparticle release modes behaved similarly in terms of collision with the surfaces. A difference was observed between CIV and PIV. Saffman lift and wall-induced lift forces having no effect, possibly due to the assumption of a porous artery wall and perpendicular outlet flow. In case of permeable artery walls, relative collision of particles with the graft wall was larger, suggesting the effect of CP of LDLs.
摘要：
本研究旨在通过评估冠状动脉移植物中血液和LDL纳米颗粒的两相流来降低移植物闭塞的风险。研究认为血液是一种不可压缩的牛顿流体,随着LDL纳米颗粒的加入，动脉壁作为多孔介质。比较了两种情况，具有恒定的入口速度（CIV）和其他具有脉动入口速度（PIV），LDL纳米颗粒受到阻力，墙壁诱导升力，诱导萨夫曼升力，或仅拖拽力。该研究还评估了壁附近LDLs（LDLs的CP）的浓度极化，通过考虑有无渗透的动脉壁。为了模拟LDL纳米颗粒，该研究在每个时间步以三种释放状态随机注射100、500和1000个纳米颗粒，使用不同的几何形状。使用COMSOL软件进行了数值模拟，结果在表格中显示为纳米粒子与墙壁的相对碰撞，图表，和剪应力等值线。研究发现，与较大的角度相比，15°的移植物植入角度具有最理想的条件，在纳米粒子与表面碰撞和闭塞方面。纳米颗粒释放模式在与表面的碰撞方面表现类似。在CIV和PIV之间观察到差异。萨夫曼升力和墙壁引起的升力没有影响，可能是由于多孔动脉壁和垂直出口流的假设。在可渗透的动脉壁的情况下，颗粒与接枝壁的相对碰撞较大，提示LDLsCP的作用。
