Maymir J C, Deutsch S, Meyer R S, Geselowitz D B, Tarbell J M
The Bioengineering Program, The Pennsylvania State University, University Park, USA.
Ann Biomed Eng. 1998 Jan-Feb;26(1):146-56. doi: 10.1114/1.86.
Laser Doppler velocimetry, with a high temporal resolution (1 ms time windows), was used to measure the flow field in two regions (major and minor orifices) near the aortic and mitral valves (Bjork Shiley monostrut Nos. 25 and 27, respectively) of the Penn State artificial heart. The motion of each valve was also investigated using a 1000 frame/s video camera in order to estimate the valve's closing velocity. Fluid velocities in excess of and opposite to valve closing velocity were detected near the valve, providing evidence of "squeeze flow." Maximum Reynolds shear stresses of approximately 20,000 dyn/cm2 and time-averaged Reynolds shear stresses of approximately 2000 dyn/cm2 were observed during the regurgitant flow phase. These elevated Reynolds shear stresses suggest that regurgitant jets play a role in the hemolysis and thrombosis associated with tilting disk heart valves in an artificial heart environment.
采用具有高时间分辨率（1毫秒时间窗口）的激光多普勒测速仪，测量了宾夕法尼亚州立大学人工心脏主动脉瓣和二尖瓣附近两个区域（主孔和小孔）的流场（分别为Bjork Shiley单支柱25号和27号）。还使用1000帧/秒的摄像机研究了每个瓣膜的运动，以估计瓣膜的关闭速度。在瓣膜附近检测到超过瓣膜关闭速度且方向相反的流体速度，这为“挤压流”提供了证据。在反流阶段观察到最大雷诺剪切应力约为20000达因/平方厘米，时间平均雷诺剪切应力约为2000达因/平方厘米。这些升高的雷诺剪切应力表明，反流射流在人工心脏环境中与倾斜盘式心脏瓣膜相关的溶血和血栓形成中起作用。
