组织工程多孔支架微管内流场数值模拟

Numerical simulation of flow field for tissue engineering scaffold microtubules

骨支架内部微管结构对营养液和细胞在其内部的流动有着非常重要的影响。利用流体计算软件Fluent对不同尺寸的人工骨微管结构内部营养液和细胞的流动状况进行了数值模拟,得到了不同几何结构骨支架内部流场的速度和压力分布图。结果表明,从进口到出口,主管道内流体流速随管道的深入不断减小。上端浮克曼管中流体流速比下端浮克曼管中流体流速高,但是比同一高度主管道内流体流速低。哈佛氏管与第一行浮克曼管交叉处下端的哈佛氏管内存在流动缓慢区,第三行浮克曼管与哈佛氏管交叉处开始,流体速度不断增大。随浮克曼管长度的增加,上端哈佛氏管中流体流动的缓慢区减小;随浮克曼管直径的增加,浮克曼管中的流速有所增加,并且各微管中流体的流速更为均匀;随浮克曼管与主管道夹角的增加,骨支架各微管内流体流速更加均匀,利于细胞和营养液在各管道的输运。本数值模拟范围内,最佳骨支架结构参数为浮克曼管长度3mm,直径0.6mm,浮克曼管与主管道夹角90°。

The microtubule structure of the bone scaffold has a considerable influence on the flow of nutrient solution and cells. The flow status of nutrient solution and cells in microtubules with different sizes was numerically simulated by using software Fluent. Velocity distribution and pressure distribution in the microtubule structure of the bone scaffold were obtained. The fluid velocity of the main pipe decreased with increasing pipe depth from inlet to outlet. The fluid velocity of the upper end of Volkmann tubes was faster than that of the lower end,but slower than that of the main pipe at the same height. A slow flowing area was observed in the intersection of the Harvard＇s tube and the first line Volkmann tube. The velocity of Harvard＇s tube increased from the intersection of the third line Volkmann tube and Harvard＇s tube. The flowing slow area at the top of the Harvard＇s tubes decreased as the length of Volkmann tubes increased. The velocity of Volkmann tubes was increasing and the flowing velocity of each tube was more uniform with the increase of the diameter of the Volkmann tubes. With increasing angle between Volkmann tubes and main pipe,the flow velocity of each scaffold tube was more uniform which was favorable for the transport of cells and nutrient solution in the pipe. In the range of this paper,the optimal parameters of bone scaffold structure were obtained as follows：Volkmann length of 3mm,diameter of 0.6mm and the angle between Volkmann tubes and the main pipe of 90°.