近年來空氣中霾害的問題越來越嚴重，造成許多人產生呼吸系統上的疾病(如氣喘)。對於氣喘患者，為有效使用藥物噴劑，探討氣管內的流場與顆粒沉積現象則為重要且有意義之研究工作。此方面之研究可分為實驗、數值模擬及理論分析。本文使用計算流體力學方法來求解穩態三維不可壓縮層流納維爾史托克之方程式以探討顆粒在正常分歧管與氣喘患者的皺摺分岐管之沉積情形。首先，本研究使用Ansys Fluent 14.5來計算正常分岐管穩態層流之顆粒沉積率，並將其所得之解與相關文獻做比較。接著進行兩種氣喘患者皺褶分岐管模型中之穩態層流計算，探討呼吸道內顆粒沉積情形。除了上述顆粒沉積情形外，也瞭解二次流與渦流等物理現象，並且比較模擬氣喘患者與正常人分岐管之管流與顆粒沉積之差異。

In the recent years, the air pollution becomes more and more worse, and many people have the respiratory diseases, such as asthma. Investigating of the flow phenomena and particle deposition in lower bifurcating airway is very important and helpful for the mechanical design on the drug deliver devices. The experiment, theoretical analysis and numerical simulation are included to study this problem. By using the computational fluid dynamic technique, the steady three-dimensional incompressible Navier-Stokes equations are solved to study the particle deposition in normal and asthmatic airway models. In this work, the commercial code Ansys Fluent 14.5 is used to study the air way flow and particle behaviors. To evaluate the accuracy a single, symmetric airway bifurcation model is adopt first, and the computed solutions are compared with those in relate papers. Furthermore a double bifurcation is introduced, and the behaviors of particle deposition are observed. In addition to the investigation of particle deposition, the present study also discusses on the secondary flow and vortex phenomena. Finally, the different behaviors of particles deposition and flow fields in the asthmatic and normal airway are compared.

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