Purpose

The main purpose is to compare the characteristics and performance of a centrifugal blood pump with and without center post. Furthermore, to propose a center post design guide for the development of centrifugal blood pumps: finding the appropriate height and diameter of the center post.

Methods

A centrifugal blood pump with different center post configurations is investigated using Computational Fluid Dynamics (CFD) in an extensive parametric approach. Height and diameter of the center post are varied on 4 levels each. Pressure head and hydraulic efficiency curves, pressure and velocity contours and volumetric histograms of scalar shear stress (SSS) distribution are discussed in detail.

Results

The simulation results show uniform pressure distribution around the casing in the baseline design. Although obtaining the minimum Normalized Index of Hemolysis (NIH), average scalar shear stress (ASSS), and volumetric percentage ratios (SSS > 9, 50 and 150 Pa), a stagnation and recirculation zone in the impeller eye above the casing bottom is detected in center post free (H = 0 mm) pump. With the establishment and further increase of the center post height, the stagnation zone disappears gradually. The results also indicate that flow recirculation and stagnation around the circumference of the center post occurs when the center post has a small diameter. As the diameter increases, a reversed flow is formed between the impeller and the center post.

Conclusions

The center post can greatly reduce the stagnation zone occurring in the center post free pump. The diameter of center post makes a difference to the flow field in the gap between the impeller and the center post.

中文翻译：

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中心立柱的建立及其设计变化对离心式旋转血泵性能的影响。

目的

主要目的是比较有无中心柱的离心血泵的特性和性能。此外，为离心式血泵的开发提出中心柱设计指南：找到合适的中心柱高度和直径。

方法

使用计算流体动力学（CFD）在广泛的参数方法中研究了具有不同中心柱配置的离心血泵。中心柱的高度和直径各有4个等级。详细讨论了压头和水力效率曲线，压力和速度等高线以及标量剪应力（SSS）分布的体积直方图。

结果

仿真结果表明，基线设计中套管周围的压力分布均匀。尽管获得了最小的标准化溶血指数（NIH），平均标量剪应力（ASSS）和体积百分比（SSS> 9、50和150 Pa），但在泵壳底部上方的叶轮眼中检测到了停滞和回流区在无中心柱（H  = 0 mm）泵中。随着中心柱高度的建立和进一步增加，停滞区逐渐消失。结果还表明，当中心柱的直径较小时，会在中心柱的圆周周围发生流动回流和停滞。随着直径的增加，在叶轮和中心柱之间形成反向流动。

结论

中心柱可大大减少在中心柱自由泵中出现的停滞区。中心柱的直径会影响叶轮和中心柱之间间隙中的流场。