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.

目錄	I
第一章  緒論	1
1-1 前言	1
1-2 研究動機及目的	5
1-3 研究過程	7
第二章  數值方法的設定與模式的模擬	9
2-1模擬模型	9
2-2 模擬方法	10
2-3參數設置	12
第三章 結果與討論	13
3-1 心瓣運動行為	13
3-2流場分析	17
第四章 結論	22
參考文獻	24
附圖	27
附表	69

1.	http://www.doh.gov.tw/CHT2006/DM/SEARCH_RESULT.aspx
2.	Leo HL, Simon HA, Dasi LP, Yoganathan AP: Effect of hinge gap width on the microflow structures in 27-mm bileaflet mechanical heart valves. The Journal of Heart Valve Disease 15: 800-808, 2006.
3.	Simon HA, Dasi LP, Leo H-L, Yoganathan AP: Spatio-temporal Flow Analysis in Bileaflet Heart Valve Hinge Regions: Potential Analysis for Blood Element Damage. Annals of Biomedical Engineering 35: 1333-1346, 2007.
4.	Hammond G.L., Geha A.S., Kopf G.S., and Hashim S.W.. Biological versus mechanical valves. J. Thorac Cardiovasc Surg. Vol.93, 182-198, 1987.
5.	Toshimasa Tokuno. Cavitation Inception of Deceleration Surfaces. Ph. D. Thesis, University of Rice, 1978.
6.	Bokros JC, LaGrange LD, Schoen FJ: Control of structure of carbon for use in bioengineering, in Walker PL (ed), Chemistry and Physics of Carbon. New York: Marcel Dekker, 103-171, 1972.
7.	Garrsion LA, Lamson TC, Deutsch S, Geselowitz DB, Gaumond RP, Tarbell JM: An in-vitro investigation of prosthetic heart valve cavitation in blood. J Heart Valve Dis 3: S8-S24, 1994.
8.	Klepetko W, Moritz A: Leaflet fracture in Edwards Duromedics bileaflet valves. J Thorac Cardiovasc Surg 97: 90-94, 1989.
9.	Kafesjian R, Wieting DW, Ely J, Chahine G, Frederik G, Watson R: Characterization of the cavitation potential of pyrolytic carbon, in Bodman E (ed), Surgery for Heart Valve Disease. London: ICR Publications, 509-516, 1990.
10.	Redaelli A, Bothorel H, Votta E, Soncini M, Morbiducci U, Del Gaudio C, Balducci A, Grigioni M: 3-D simulation of St. Jude Medical bileaflet valve opening process: fluid-structure interaction study and experiment validation. J Heart Valve Dis 13: 804-813, 2004.
11.	Ge L, Dasi LP, Sotiropoulos F, Yoganathan AP: Characterization of hemodynamic forces induced by mechanical heart valves: Renolds vs. viscous stresses. Annals of Biomedical Engineering 36: 276-297, 2008.
12.	Dumont K, Stijnen JMA, Vierendeels J, Van De Vosse FN, Verdonck PR: Validation of a fluid-structure interaction model of a heart valve using the dynamic mesh method in Fluent. Computer Methods in Biomechanics and Biomedical Engineering 7: 139-146, 2004.
13.	Dasi LP, Ge L, Simon HA, Sotiropoulos F, Yoganathan AP: Vorticity dynamics of a bileaflet mechanical heart vlave in an axisymmetric aorta. Phys. Fluids 19: 067105, 2007.
14.	Choi CR, kim CN: Numerical Analysis on the Hemodynamics and Leaflet Dynamics in a Bileaflet Mechanical Heart Valve Using a Fluid-Structure Interaction Method. ASAIO Journal 55: 428-437, 2009.
15.	Bang JS, Yoo SM, Kim CN: Characteristics of Pulsatile Blood Flow Through the Curved Bileaflet Mechanical Heart Valve Installed in Two Different Types of Blood Vessels: Velocity and Pressure of Blood Flow. ASAIO Journal 52: 234-242, 2006.
16.	Nobili M, Morbiducci U, Ponzini R, Del Gaudio C, Balducci A, Grigioni M, Maria Montevecchi F, Redaelli A: Numerical simulation of the dynamics of a bileaflet prosthetic heart valve using a fluid-structure interaction approach. Journal of Biomechanics 41: 2539-2550, 2008.
17.	Ge L, Sotiropoulos F: A Numerical Method for Solving the 3D Unsteady Incompressible Navier-Stokes Equations in Curvilinear Domains with Complex Immersed Boundaries. Journal of Computational Physics 225: 1782-1809, 2007.
18.	Dumont K, Vierendeels J, Verdonck PR: Feasibility study of the dynamic mesh model in Fluent for fluid-structure interaction of a heart valve, in Brebbia CA, Arnez ZM, Solina F, Stankovski V (ed), Simulations in Biomedicine V. Advances in Computational Bioengineering. Boston: WIT Press, Southampton, 169-176, 2003.
19.	Vierendeels J, Dumont K, Dick E, Verdonck PR: Stabilization of a fluid-structure coupling procedure for rigid body motion. Proceeding of the 33rd AIAA Fluid Dynamics Conference and Exhibit 3720, 2003.
20.	Li CP, Chen SF, Lo CW, Lu PC. Turbulence characteristics downstream of a new trileaflet mechanical heart vakve. ASAIO J. 2011;57:188-96.
21.	D. C. Wilcox. Multiscale model for turbulent flows. American Institute of Aeronautics Journal 26(11): 1311-20, 1988.
22.	S. V. Patankar, D. B. Spalding , “ A Calculation Procedure for Heat, Mass and Momentum Transfer in Three-Dimensional Parabolic Flows ”, Int. J. Heat Transfer, vol.15, pp.1787-1806, 1972.
23.	Bellhouse BJ, Talbot L. The fluid mechanics of the aortic valve. J Fluid Mech. 1969;35:721-35.
24.	Lu PC, Liu JS, Huang RH, Lo CW, Lai HC, Hwang NHC. The closing behavior of mechanical aortic heart valve prostheses. ASAIO J. 2004;50:294-300.
25.	Li CP, Lu PC. Numerical comparison of the closing dynamics of a new trileaflet and a bileaflet mechanical aortic heart valve. J Artif Organs. 2012;online first.