本研究使用質點軌跡流場觀察法與質點影像速度儀，針對一個具有三支分歧管的玻璃管，模擬人體的主動脈弓及三支分歧血管(臂頭動脈、左頸總動脈及左鎖骨下動脈)。當支架裝置於臂頭動脈時，研究主動脈弓的動態流場與壁面剪應力。為了簡化實驗複雜度，使用甘油與水的混合物作為工作流體。利用血液泵模擬心臟的脈動，每分鐘72個脈動衝程，每個衝程的流量為70毫升，每個衝程的收縮與舒張比例為45%/55%，流體溫度、Womersley parameter及時間平均雷諾數分別為37 oC、16.34及1167。在收縮與舒張過程中，觀察管內流場之時間與空間的流場結構衍化，並量測速度分佈與壁面剪應力。在收縮相位時，速度邊界層在靠近主動脈弓轉彎處分離，分離邊界層產生回流增加血小板堆積的可能性，另外，強烈的回流在舒張相位時被產生。在主動脈弓與分歧管的交接處存在小的壁面剪應力，在主動脈的外管壁存在較大的壁面剪應力。因此，動脈硬化及血管損害的潛在風險將發生在這些區域。藉由安裝支架在臂頭動脈，能夠降低壁面剪應力及縮小分離區，並且延遲不適當的流場結構形成在主動脈弓的轉彎處及主動脈弓與分歧管的交接處。此外，根據分析壁面剪應力在收縮與舒張時隨著時間的變化，安裝支架技術能夠改善血管的流體結構。

Pulsatile in a model simulating an aortic arch with and without a stent installed in brachiocephalic were analyzed by using particle tracking flow visualization method and particle image velocimetry (PIV). The model was an U-shaped transparent glass tube with three main branches (brachiocephalic artery, left common carotid artery, and left subclavian artery). The working fluid was a mixture of water and glycerol which simulates the viscosity of blood. Pulsatile flow simulating the output of a human heart beat was supplied by a pulsatile blood pump. The initial conditions set for this study were: 72 strokes/minute (1.2 Hz) stroke rate, 70 ml/stroke volume rate, and 45%/55% of systole/diastole ratio. The temperature, Womersley parameter, and time-averaged Reynolds number were 37oC, 16.34 and 1167, respectively. The temporal/spatial evolution processes of the flow pattern, velocity distribution, and wall shear stress during systolic and diastolic phases were presented and discussed. During the systole phase, the boundary layer on the inner wall separated from the area near the turning arch where the thoracic aorta descends. The induced reverse flow increased the probability of plaque deposition while the strong reverse flow was produced in the arch during diastolic phase. The shear stress showed low values at entrance of branches and particularly high values around the outer wall of ascending and descending aorta. Hence, the potential risk of atherosclerosis and damage to vascular are easy to happen at these locations. Placing the stent in the brachiocephalic of aorta could decrease the wall shear stress at some locations, suppress size of separation region, and postpone appearance of bad flow structure in some areas along aortic arch and three main branches. Furthermore, according to the oscillation of wall shear stress with time during systole and diastole cycle due to the effect of stent, the present result was expected to be useful for further improvements in placing of stent technology in vascular.

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