為了研究氣管內流場受重力及受傷切半後的影響, 我們利用數值方法模擬及探討
其效應, 本研究分為三個部分: 第一, 完整的韋伯模型氣管和真實氣管在不同呼吸
狀態下流場與氧氣殘留率的差異。第二, 經手術後截半氣管和完整氣管在不同呼
吸狀態下的流場變化, 氧氣濃度分佈與氧氣殘留量。第三, 考慮重力效應, 觀察完
整的韋伯模型氣管和真實氣管在不同呼吸狀態下, 呼吸流場、氧氣濃度以及氧氣
殘留率的差異。
我們觀察不同呼吸狀態下的氧氣殘留率發現, 若是增加吸入氣體的體積, 殘
留的氧氣體積會增加。若是降低呼吸的頻率, 氧氣殘留率也會隨之增加。模擬完
整韋伯模型氣管和真實氣管的氧氣殘留率發現, 真實氣管除了分歧區域和外側的
迴流, 在管壁凹槽處的迴流會提高氧氣殘留率, 使得真實氣管的氧氣殘留率比韋
伯模型氣管的氧氣殘留率高。比較術後截半與完整氣管的氧氣殘留率, 截半氣管
的氧氣殘留率比完整氣管的氧氣殘留率差。在呼氣時, 有重力效應下的迴流區域
比無重力影響下的大, 使氧氣不易隨呼氣的力量所帶走, 導致有重力效應下的氧
氣殘留率比無重力影響下高。

The aim of this study is to use numerical approaches to simulate flow patterns
under the gravity effect and the influence of the bronchial tree.First,all of we analyze flow patterns under a variety of breathing conditions and evaluate the rate of remained oxygen in Weibel and real bronchial trees. Second,we compare flow patterns,the variations of oxygen and the rate of remained oxygen for whole and half bronchial trees after surgery. Third, we observe flow patterns, the variations of oxygen and the rate of remained oxygen under the gravity effect. We find that increasing respiratory volume can enhance the rate of remained volume of oxygen. However, decreasing breathing frequency may also improve the rate of remained oxygen. In addition to separation region in bifurcated area and the outside walls, cavities on inner walls of the real bronchial tree can capture more oxygen than a Weibel model. As a result, the rate of remained oxygen of the real bronchial tree is better than the Weibel bronchial tree. Comparison with whole and half bronchial trees after surgery, the rate of remained oxygen of the half bronchial tree is worse than the whole bronchial tree. At last, we find that the recirculation regions in the Weibel bronchial tree under gravity effect is larger than without gravity. Hence, the rate of remained oxygen of the bronchial tree with gravity is better than without gravity.

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