Development of meso scale flow analysis method to develop biocompatible artificial hearts

为建立一种介观流动分析方法，开发生物相容性良好的人工心脏，提出了一种基于三维双向粒子法的计算模型。血浆流体由SPH颗粒离散化，并且红细胞（RBC）由被弹性膜（结构）颗粒包围的内部SPH颗粒表示。为了验证该模型，我们数值分析了恒定剪切场下红细胞的三维坦克踏板运动。数值模拟结果能较好地再现红细胞的运动行为。发展了空间分辨率为10 μ m量级的微观定量流动显示方法，用于研究人工心脏表面的流场。通过对旋转剪切应力器内外筒间差距内的微观流动进行观测，研究了内筒表面粗糙度变化对流动的影响。因此，一个小的轮廓差异是 ...更多信息 在圆周速度中观察到由几微米的表面粗糙度变化引起的。虽然表面粗糙度的变化引起的湍流强度差异已被预测，但几乎没有观察到显着的湍流强度差异引起的表面粗糙度的变化。定量评价使用旋转剪切应力和新鲜牛血，以澄清人工心脏的表面粗糙度和溶血水平之间的关系。在3，750 s^的层流剪切流条件下，发现溶血快速增加的粗糙度阈值存在于Ra0.6 μm和Ra0.8 μm之间<-1>。磁悬浮泵作为血液相容性的测试工具而被开发。研制的人工心脏具有良好的泵送性能。最大压头、流量分别大于200 mm Hg和10 L/min。开发的磁悬浮泵将被用来作为工具，研究溶血和表面粗糙度之间的关系。少

Following studies were investigated to establish a mesoscopic flow analysis method to develop good biocompatible artificial hearts.A new computational model based on three-dimensional two-way particle method was invented. Plasma fluid is discretized by SPH particles, and a red blood cell (RBC) is expressed by internal SPH particles surrounded by elastic membrane (structure) particles. For verifying the model, we numerically analyzed the three-dimensional tank-tread motion of an RBC under a constant shear field. The numerical results can well reproduce behaviors of RBC.The microscopic quantitative flow visualization method, whose space resolution was 10 micro-meter order, was developed to investigate the flow field on the artificial heart surface. Micro flow in the gap between the inner and the outer cylinder of the rotational shear stressor was observed to clarify flow condition caused by the surface roughness variation on the inner cylinder. As a result, a small profile difference was … More observed in the circumferential velocity that was caused by the a few micrometer surface roughness variation. Although the turbulent intensity difference had been predicted caused by the surface roughness variation, remarkable turbulent intensity difference was hardly observed caused by a 'surface roughness variation.Quantitative evaluation was carried out using a rotational shear stressor and fresh bovine blood to clarify the relationship between the surface roughness of artificial hearts and hemolysis level. A threshold of the roughness for a rapid increase in hemolysis was found to exist between Ra0.6 μm and Ra0.8 μm under a laminar shear flow condition of 3,750 s^<-1>. Magnetically suspended pumps were developed as a test tool for the hemocompatibility. Developed artificial hearts displayed sufficient pump performance. Maximum pressure head, flow rate are more than 200 mm Hg and 10L/min, respectively. Developed maglev pumps will be used as tools to investigated the relationship between hemolysis and surface roughness. Less