Development of a low-priced artificial heart, valve with high valvular functions

第一年，从价格、机械强度、机械性能和加工后的表面状况等方面考虑，选择超硬铝作为人工心脏瓣膜的材料。在计算机模拟和流场显示研究中，发现在瓣叶远端和瓣环周围都存在着滞止和旋涡，在中心流型双叶瓣中获得了相对稳定的流态。采用溅射法在超硬铝皮瓣表面沉积氧化铝，以提高皮瓣的耐久性和血液相容性。反应溅射比常规溅射沉积更光滑和更强的膜。通过插入功能梯度材料的耐久性和附着力的膜增加了两倍。在第二年阀的设计确定基于流体动力学在静态和动态流动测试。挡板由枢轴支撑并且在关闭位置倾斜。该阀具有较大的小节流孔，以获得足够的二次流量。激活接触凝血因子和血小板。检查了在烧结机沉积的氧化铝上的粘附性。实验表明氧化铝具有与生物材料一样好的血液相容性。在过去的一年中，根据静态和动态流动实验以及流动可视化研究确定了皮瓣的曲率，pivol的位置和皮瓣的打开角度。最佳曲率为9%，支点位置为70%，张开角度为67 °。阀环由不锈钢机械加工而成，并且表面由TiN涂覆。阀环也可以由钛加工而成。我们还开发了一种加速耐久性试验系统，其速度比其他系统高出三倍，并且具有较低的水锤压力。

In the first year ultra-duralumin was selected as a material to construct an artificial heart valve from the standpoints of price, mechanical strength, machanibility, and surface condition after machining. Stagnation and vortexes were observed in the regions distal to valve flaps and also around valve ring of commercially available valves in both computer simulation and flow visualization studies, Relatively stable flow pattern was obtained in the developed central flow-type bileaflet valve with arched flaps. Alumina was deposited on the ultra-duralumin flaps by sputtering to immprove durability and blood compatibility. Reactive sputtering deposited smoother and stronger membrane than conventional sputtering. By interposing functionally gradient material durability and adhesion of the film increased twice.In the second year valve design was determined based on fluid dynamics in both static and dynamic flow tests. The flaps are supported by pivots and inclined at the closed position. The valve has relatively large minor orifice to obtain enough secondary flow. Activation of contact coagulation factor and also platelet. Adhesion on the sputter-deposited alumina were examined. The experiments disclosed that the alumina has as good blood ompatibility as biomaterials.In the last year curvature of the flap, position of the pivol, and opening angle of the flap were determined based on static and dynamic flow tests and also flow visualization studies. The optimun curvature was 9%, pivot position 70%, and opening angle 67 degrees. The valve ring was machined from stainless steel and the surface was coated by TIN. The valve ring can also be machined from titanium. We also developed an accelerated endurance test system with the speed three times higher than other systems and also with lower water hammer pressure.