許多統計資料指出，心血管疾病是現代人死亡原因的前幾名，而心臟瓣膜的疾病就是其中一種。心臟瓣膜置換手術對心臟病患者已經是一個發展健全且有效的治療方式。然而過去的研究結果指出，通過單葉片或雙葉片機械心瓣的流場容易造成溶血及血栓之現象。而發生之可能原因包含流場中之切應力過大，以及葉片的關閉速度過快造成穴蝕的發生，當穴蝕汽泡爆破時，產生之高壓會破壞血球及血小板。三葉片機械心瓣主要是依靠主動脈竇中之渦漩來幫助葉片之關閉，與單葉片或雙葉片機械心瓣依靠反向流推動葉片來關閉不同，因此其葉片的關閉速度較為緩慢，可以減少穴蝕發生的機會。本研究利用數值模擬的商用軟體Fluent，模擬這雙葉及三葉機械心瓣的流場，並與過去學者做比較，以確認模擬之結果是否正確，期望對於日後三葉片機械心瓣的研發上有所助益。 A lot of statistical data indicate that cardiovascular disease is the first several cause of death of modern people, and heart valve disease is on of them. Heart valve replacement surgery is a well developed and efficient therapeutic option for terminally ill cardiac patients. Previous researchers indicated that the phenomenon of hemolysis and thrombosis would occur in the flow fields across the monoleaflet or bileaflet mechanical heart valves. The probable reasons of causing hemolysis and thrombosis included shear stresses in the flow fields might be large enough to damage red blood cells, and the closing velocity of the leaflet was excessively large to cause cavitation phenomenon. Commercial software Fluent was also applied to run numerical simulations of these two valves in this study. The results of numerical simulations would be valid with the experiments and were expected to be useful for the development of the trileaflet valve in the future.
