本研究採用＃27的St. Jude Medical（SJM）雙葉片機械人工心瓣進行主動脈體外循環，實驗主要模擬人體左心循環運作，其參數設定為符合人體的血壓及流量波形，壓力的設定主動脈壓為80~120mmHg；左心室壓為0~120mmHg；心跳頻率為每分鐘70下、90下、120下，其每分鐘心臟輸出量為5升、6升、7.5升。利用質點流速儀（Digital Particle Image Velocimetry, DPIV）於主動脈瓣上游端進行心瓣關閉瞬間流場量測。量測位置位於心臟關閉時能產生回流量的位置，即主動脈瓣上游端葉片與葉片之間和葉片與心瓣環座之間。DPIV受PCB壓力計的觸發量測心瓣關閉瞬間流場，利用延遲產生器觸發0.3ms、2ms、5ms、10ms四個時間相位。利用Rankine vortex模式進行渦漩的定量分析，即可求出渦漩中心半徑、切向速度、環流強度與壓降值。
    近年來，許多學者表示流體回流速度比流體往前流流速大，故本實驗發現心瓣關閉瞬間於葉片間隙中央會產生高速的反向流。因此，心臟瓣膜關閉瞬間所產生的的高流速，可能會破壞血球和心臟瓣膜本身。心瓣關閉瞬間因為反彈作用與高速噴射流會形成渦漩，由DPIV量測可證實有渦漩形成。若渦漩中心壓降低於蒸氣壓(-740 mmHg)就會發生穴蝕現象，本實驗所量測出來的最大壓降為14.856mmHg，所以並不會有穴蝕現象產生。

The SJM 25 mm bileaflet test valve was positioned in the aorta position of a pulsatile mock circulatory loop system. The main experimental simulation human the left cardiac cycle. Its parameters set to comply with the body's blood pressure and flow waveforms, the pressures in the aortic, left ventricle and left atrium were maintained at 80-120 mmHg, 0-120 mmHg and 5-7 mmHg. The pulse rates were set at 70, 90, and 120 bpm, with respective to the cardiac outputs of 5 L/min, 6 L/min, and 7.5 L/min. The heart valves shut down instantly, the flow field measurements were made with a Digital Particle Image velocimeter (DPIV) at the upstream end of aortic heart valves. The measurement points were primarily located at gaps between the closed leaflets during closure, between the leaflets and housing ring. The DPIV system was triggered by a PCB, it was also used to further trigger a pulse delay generator for instantaneous measurement of the flow field at 0.3, 2, 5, and 10 ms after the impact. And we use Rankine vortex model to quantitatively analyze the role of vortex, that contains information about vortex core redius, tangential velocity, circulation strength and maximum pressure drop. 
In recent years, many scholars have found that the backflow velocity is relatively large than the forward flow in the valve closure. Results show that the peak values of backflow flow velocity during closure are concentrate at the center of the gap between the leaflets, that bring about the peak velocity. So the heart valves shut down instantly generate high flow rate, may damage blood cells and heart valves.
It’s noted that instantaneous valve closure,occluder rebound and high-speed leakage flow generate vortices. The PIV measurements confirmed the formation of these large-scale vortices. The maximum pressure drop in the vortex center is roughly 14.856 mmHg. Since cavitation formation requires the local pressure to drop below vapor pressure (about -740 mmHg),Our results clearly showed that vortex formation with a pressure drop of this order of magnitude cannot provide significant contribution to mechanical heart valve cavitation.

目錄
圖目錄……………………………………………………………………VI
                                                        
表目錄……………………………………………………………………XI

第一章  緒論……………………………………………………………1
1-1  前言…………………………………………………………………1
1-2  研究動機及目的……………………………………………………3
1-3  研究程序……………………………………………………………4
第二章  文獻回顧………………………………………………………7
2-1  人工機械心瓣………………………………………………………7
2-2 回流流場相關研究…………………………………………………9
     2-3 渦流相關成因………………………………………………10
     2-4 渦漩相關研究………………………………………………14
     2-5 葉片關閉行為………………………………………………17
第三章 實驗設置及方法………………………………………………18
3-1 體外模擬循環系統…………………………………………………18
3-2 壓力計………………………………………………………………20
3-3 高速攝影機…………………………………………………………22
3-4數位質點影像測速系統……………………………………………23
3-5實驗條件與量測位置………………………………………………25
     3-6公式運算………………………………………………………28
3-7資料分析……………………………………………………………32
第四章 結果與討論……………………………………………………35
4-1 主動脈關閉行為量測………………………………………………35
4-2 壓力波形……………………………………………………………37
     4-3 渦流流場量測分析………………………………………….39
     4-3-1 中央孔口關閉瞬間產生之渦流………………………….40
     4-3-2 側邊孔口關閉瞬間產生之渦流………………………….59
4-4回流流場量測分析…………………………………………………74
4-4-1中央孔口關閉瞬間之回流速度…………………………………74
4-4-2側邊孔口關閉瞬間之回流速度…………………………………89
第五章 結論……………………………………………………………103
參考文獻………………………………………………………………105


圖目錄
圖1-1 研究流程示意圖…………………………………………………6
圖3-1 體外模擬循環系統架構圖………………………………………19
圖3-2-1 高頻率壓力計…………………………………………………20
圖3-2-2 生理壓力計……………………………………………………21
圖3-2-3  Millar壓力計………………………………………………21
圖3-3-1 高速攝影機……………………………………………………22
圖3-4-1 數位質點影像測速儀…………………………………………24
圖3-5-1 St. Jude Medical雙葉片心瓣………………………………25
圖3-4-3 人體主動脈壓、左心室壓、左心房壓及流量之波形週期…26
圖3-5-3  DPIV量測段示意圖…………………………………………27
圖3-5-4  三竇管搭配SJM雙葉瓣之示意圖……………………………27
圖3-6-1  Rankine vortex模式………………………………………29
圖 3-7-2 DPIV分析程式 ………………………………………………34
圖4-1  SJM雙葉瓣開關行為……………………………………………36
圖4-2 心跳頻率70bpm的PCB、AOP及LVP壓力波形相位圖……………37
圖4-3 心跳頻率90bpm的PCB、AOP及LVP壓力波形相位圖……………38
圖4-4 心跳頻率120bpm的PCB、AOP及LVP壓力波形相位圖…………38
圖4-5 中心孔口左渦漩半徑 之表示圖………………………………43
圖4-6中心孔口左渦漩速度 之表示圖…………………………………44
圖4-7中心孔口左渦漩環流強度 之表示圖……………………………45
圖4-8中心孔口左渦漩壓降 之表示圖…………………………………46
圖4-9 中央孔口右渦漩半徑 之表示圖………………………………49
圖4-10中心孔口右渦漩速度 之表示圖………………………………50
圖4-11中心孔口右渦漩環流強度 之表示圖…………………………51
圖4-12中心孔口右渦漩壓降 之表示圖………………………………52
圖4-13 心瓣關閉後0.3ms於中央孔口之瞬時向量流場（70bpm）…53
圖4-14 心瓣關閉後2ms於中央孔口之瞬時向量流場（70bpm）……53
圖4-15 心瓣關閉後5ms於中央孔口之瞬時向量流場（70bpm）……54
圖4-16 心瓣關閉後10ms於中央孔口之瞬時向量流場（70bpm）……54
圖4-17 心瓣關閉後0.3ms於中央孔口之瞬時向量流場（90bpm）…55
圖4-18 心瓣關閉後2ms於中央孔口之瞬時向量流場（90bpm）……55
圖4-19 心瓣關閉後5ms於中央孔口之瞬時向量流場（90bpm）……56
圖4-20 心瓣關閉後10ms於中央孔口之瞬時向量流場（90bpm）……56
圖4-21 心瓣關閉後0.3ms於中央孔口之瞬時向量流場（120bpm）…57
圖4-22 心瓣關閉後2ms於中央孔口之瞬時向量流場（120bpm）……57
圖4-23 心瓣關閉後5ms於中央孔口之瞬時向量流場（120bpm）……58
圖4-24 心瓣關閉後10ms於中央孔口之瞬時向量流場（120bpm）…58
圖4-25 側邊孔口渦漩半徑 之表示圖…………………………………64
圖4-26 側邊孔口渦漩速度 之表示圖………………………………65
圖4-27側邊孔口渦漩環流強度 之表示圖……………………………66
圖4-28側邊孔口渦漩壓降 之表示圖…………………………………67
圖4-29 心瓣關閉後0.3ms於側邊孔口之瞬時向量流場（70bpm）…68
圖4-30 心瓣關閉後2ms於側邊孔口之瞬時向量流場（70bpm）……68
圖4-31 心瓣關閉後5ms於側邊孔口之瞬時向量流場（70bpm）……69
圖4-32 心瓣關閉後10ms於側邊孔口之瞬時向量流場（70bpm）……69
圖4-33 心瓣關閉後0.3ms於側邊孔口之瞬時向量流場（90bpm）…70
圖4-34 心瓣關閉後2ms於側邊孔口之瞬時向量流場（90bpm）……70
圖4-35 心瓣關閉後5ms於側邊孔口之瞬時向量流場（90bpm）……71
圖4-36 心瓣關閉後10ms於側邊孔口之瞬時向量流場（90bpm）……71
圖4-37 心瓣關閉後0.3ms於側邊孔口之瞬時向量流場（120bpm）…72
圖4-38 心瓣關閉後2ms於側邊孔口之瞬時向量流場（120bpm）……72
圖4-39 心瓣關閉後5ms於側邊孔口之瞬時向量流場（120bpm）……73
圖4-40 心瓣關閉後10ms於側邊孔口之瞬時向量流場（120bpm）…73
圖4-41 中央孔口回流流場（A）70bpm-0.3ms………………………83
圖4-42 中央孔口回流流場（B）70bpm-2ms…………………………83
圖4-43 中央孔口回流流場（C）70bpm-5ms…………………………84
圖4-44 中央孔口回流流場（D）70bpm-10ms…………………………84
圖4-45 中央孔口回流流場（E）90bpm-0.3ms………………………85
圖4-46 中央孔口回流流場（F）90bpm-2ms…………………………85
圖4-47 中央孔口回流流場（G）90bpm-5ms…………………………86
圖4-48 中央孔口回流流場（H）90bpm-10ms…………………………86
圖4-49 中央孔口回流流場（I）120bpm-0.3ms………………………87
圖4-50 中央孔口回流流場（J）120bpm-2ms…………………………87
圖4-51 中央孔口回流流場（K）120bpm-5ms…………………………88
圖4-52 中央孔口回流流場（L）120bpm-10ms………………………88
圖4-53 側邊孔口回流流場（a）70bpm-0.3ms………………………97
圖4-54 側邊孔口回流流場（b）70bpm-2ms…………………………97
圖4-55 側邊孔口回流流場（c）70bpm-5ms…………………………98
圖4-56 側邊孔口回流流場（d）70bpm-10ms…………………………98
圖4-57 側邊孔口回流流場（e）90bpm-0.3ms………………………99
圖4-58 側邊孔口回流流場（f）90bpm-2ms…………………………99
圖4-59 側邊孔口回流流場（g）90bpm-5ms…………………………100
圖4-60 側邊孔口回流流場（h）90bpm-10ms………………………100
圖4-61 側邊孔口回流流場（i）120bpm-0.3ms……………………101
圖4-62 側邊孔口回流流場（j）120bpm-2ms………………………101
圖4-63 側邊孔口回流流場（k）120bpm-5ms………………………102
圖4-64 側邊孔口回流流場（l）120bpm-10ms………………………102



表目錄
表2-2 渦流的中心點之壓降計算………………………………………14
表4-1 中心孔口左渦漩半徑R（mm）…………………………………43
表4-2 中心孔口左渦漩速度Vt（m/s）………………………………44
表4-3 中心孔口左渦漩環流強度C（m^2/s ）………………………45
表4-4 中心孔口左渦漩壓降dp（mmHg）………………………………46
表4-5中心孔口右渦漩半徑R（mm）……………………………………49
表4-6中心孔口右渦漩速度Vt（m/s）…………………………………50
表4-7中心孔口右渦漩環流強度C（m^2/s）…………………………51
表4-8中心孔口右渦漩壓降dp（mmHg）………………………………52
表4-9 側邊孔口渦漩半徑R（mm）……………………………………64
表4-10 側邊孔口渦漩速度Vt（m/s）…………………………………65
表4-11側邊孔口渦漩環流強度C（m^2/s）……………………………66
表4-12 側邊孔口渦漩壓降dp（mmHg）………………………………67
表4-13 中央孔口最大平均回流速度（m/s）…………………………82

1. 周宥節, 2006, 三葉片機械心瓣葉片軸承功能特性研究, 淡江大學水資源及環境工程學系碩士論文.
2. Yoganathan AP. Cardiac Valve Prostheses, The Biomedical  Engineering Handbook, Bronzino J, editor, CRC Press, Boca Raton, Florida 2000; 1847-1870.
3. Schoen FJ, Kujovich JL, Levy RJ et al.  Bioprosthetic Valve Failure Cardiov Clin 1988; 18(2) 289-3. 
4. Hwang NH. Cavitation Potential of Pyrolytic Carbon Heart Valve Prostheses：A Review and Current Status, The Journal of Heart Valve Disease 1998; 7 140-150.
5. Hammond GL et al., Biological versus mechanical valves. . Thorac Cardiovasc Surg,1987. 93:p.p. 182-198.  
6. Reul H, Schmitz B, Rau G. In vitro comparison of bileaflet aortic heart valve prostheses-St. Jude Medical, CarboMedics, modified Edwards-DuroMedics, and Sorin-Bicarbon valves. The Journal of Thoracic Cardiovascular Surgery 106：412-420,1993.
7. 徐瑞蓮, 1998, 主動脈雙葉片人工心瓣之回流流場量測, 淡江大學水資源及環境工程學系碩士論文.
8. Manning KB, Kini V, Fontaine AA, Deutsch S, Tarbell JM 2003           
  Regurgitant Flow Field Characteristics of the St. Jude Bileaflet Mechanical Heart Valve under Physiologic Pulsatile Flow Using Particle Image Velocimetry, Artificial Organs 27(9) 840-846.
9. Kini V, Bachmann C, Fontaine A, Deutsh S, T	arbell JM 2001       Integrating Particle Image Velocimetry and Laser Doppler Velocimetry Measurements of the Regurgitant Flow Field Past Mechanical Heart Valves, Artificial Organs 25(2) 136-145.
10. Toshimasa Tokuno.Cavitation Inception of Deceleration Surfaces. Ph. D. Thesis, University of Rice,1978.
11. Zapanta CM 1997 CORRELATION OF PROSTHETIC HEART VALVE DYNAMICS WITH CAVITATION: IN VITRO AND IN VIVO STUDIES, Ph. D. Thesis, The Pennsylvania State University.
12. Bluestein D, Einav S, Hwang NHC 1994 A Squeeze Flow Phenomenon at the Closing of a Bileaflet Mechanical Heart Valve Prosthesis, J. Biomechanics 27(11) 1369-1378.
13. Bachmann C, Kini V, Deutsch S, Fontaine AA, Tarbell JM 2002 Mechanisms of Cavitation and the Formation of Stable Bubbles on the Björk-Shiley Monostrut Prosthetic Heart Valve, The Journal of Heart Valve Disease ,11 105-113.
14. Bachmann C, kini V, Deutsch S, Fontaine AA, Tarbell JM. Mechanisms of Csvitation and Formation of Stable Bubbles on the Bjork-Shiley Monostrut Prosthetic Heart Valve. The Journal of Heart Valve Disease 2002; 11:105-113.
15. Kini V, Bachmann C, Fontaine A, Deutsch S, Tarbell JM Flow Visualization in Mechanical Heart Valves: Occluder Rebound and Cavitation Potential, Annals of Biomedical Engineering 2000; 28 431-441.
16. Manning KB, Kini V, Fontaine AA, Deutsch S, and Tarbell JM. Regurgitant Flow Field Characteristics of the St. Jude Bileaflet Mechanical Heart Valve under Physiologic Pulsatile Flow Using Particle Image Velocimetry. Artificial Organs 2003; 27（a）：840-846.
17. Manning KB, Przybysz TM, Fontaine AA, Tarbell JM, and Deutsch S. Near Field Flow Characteristics of the Bjork-Shiley Monostrut Valve in a Modified Single Shot Valve Chamber. ASAIO Journal 2005; 51:133-138.
18. Kini V, Bachmann C, Fontaine A, Deutsch S, Tarbell JM Integrating Particle Image Velocimetry and Laser Doppler Velocimetry Measurements of the Regurgitant Flow Field Past Mechanical Heart Valves, Artificial Organs 2001; 25(2) 136-145.
19. Manning KB, Kini V, Fontaine AA, Deutsch S, Tarbell JM  Regurgitant Flow Field Characteristics of the St. Jude Bileaflet Mechanical Heart Valve under Physiologic Pulsatile Flow Using Particle Image Velocimetry, Artificial Organs 2003; 27(9) 840-846.
20. Manning KB, Przybysz TM, Fortaine AA, et al. Mechanical Heart Valve Cavitation Fluid Mechanics ASAIO J. 2004; 50(2) 123.
21. Rambod E, Beizaie M, Shusser M, Milo S, Gharib M A physical model describing the mechanism for formation of gas microbubbles in patients with mitral mechanical heart valves, Annals of Biomedical Engineering. 1999; 27: 774-792.
22. Milo S, Gutfinger C, Chu GYC, Gharib M  Bubble Formation on SJ. Jude Mechanical Heart Valves- An In Vitro Study, The Journal of Heart Valve Disease 2003; 12 406-410.
23. Milo S, Gutfinger C, Chu GYC, Gharib M  Bubble Formation on SJ. Jude Mechanical Heart Valves- An In Vitro Study, The Journal of Heart Valve Disease 2005; 12: 406-410.
24. Rambod E, Beizaie M, Sahn DJ, Gharib M: Role of vortices in growth of microbubbles at mitral mechanical heart valve closure, Ann Biomed Eng 2007; 35(7): 1131-1145.
25. Li CP, Lu PC, Liu JS, Lo CW, Hwang NH, Role of Vortices in Cavitation Formation in the FlowAcross a Mechanical Heart Valve,The Journal of Heart Valve Disease 2008;17:435-445.
26. Lu PC, Liu JS, Huang RH, Lo CW, Lai HC, Hwang HC, The Closing Behavior of Mechanical Aortic Heart Valve Prostheses, ASAIO Journal 2004；50:294-300.
27. Kontt E, Reul H, Knoch M, Steinseifer U, Rau G (1998). In vitro comparison of aortic heart valve prostheses. Part 1. Mechanical valves. Journal of Thoracic Cardiovascular Surgery  96:952-961.
28. Li CP, Chen SF, Lo CW, Lu PC, Role of Vortices in Cavitation Formation in the Flow at the Closure of a Bileaflet Mitral Mechanical Heart Valve, Artificial Organs 2011.
29. 蔡伯昌, 2012, 在不同主動脈形狀下機械心瓣的流動特性, 淡江大學水資源及環境工程學系碩士論文.