Baldwin J T, Deutsch S, Geselowitz D B, Tarbell J M
Bioengineering Program, Pennsylvania State University, University Park 16802.
J Biomech Eng. 1994 May;116(2):190-200. doi: 10.1115/1.2895719.
Laser Doppler Anemometry measurements of mean (ensemble average) velocities and turbulent (Reynolds) stresses at 140 locations within the left ventricle of the Penn State 70 cc electric artificial heart/ventricular assist device are reported at 8 times during the cardiac cycle. Mean velocity patterns indicate that the surfaces of the blood sac and valve tracts are exposed to significant levels of wall shear stress (good wall washing) during some portion of the flow cycle, and there is no location where the flow is stagnant over the entire flow cycle. This implies that thrombus deposition within the artificial heart should be suppressed. Turbulent stresses in the main pumping chamber and the outflow tracts of the tilting disk valves do not exceed 2000 dynes/cm2. The highest turbulent stresses (20,000 dynes/cm2) and smallest turbulent microscales (6 microns) are found in the regurgitant jets on the minor orifice side of the aortic valve during diastole and the mitral valve during systole. Taken together, the data suggest that improvements in artificial heart fluid mechanics will come through valve design and pump operating conditions, not pumping chamber design.
报告了在宾夕法尼亚州立大学70立方厘米电动人工心脏/心室辅助装置左心室内140个位置处，在心动周期的8个时刻进行的激光多普勒风速测量，测量了平均（总体平均）速度和湍流（雷诺）应力。平均速度模式表明，在流动周期的某些部分，血囊和瓣膜通道表面承受着显著水平的壁面剪应力（良好的壁面冲刷），并且在整个流动周期中没有任何位置的流动是停滞的。这意味着人工心脏内血栓的沉积应受到抑制。主泵腔和倾斜盘式瓣膜流出道中的湍流应力不超过2000达因/平方厘米。在舒张期主动脉瓣小开口侧和收缩期二尖瓣的反流射流中发现了最高的湍流应力（20000达因/平方厘米）和最小的湍流微尺度（6微米）。综合来看，数据表明人工心脏流体力学的改进将通过瓣膜设计和泵的运行条件实现，而不是通过泵腔设计。
