適應性計算應用於人體鼻腔呼吸時空氣流動特性分析

本文研究的目的為使用三維非穩態紊流模式，在人體正常呼吸狀態下對空氣流經人體上呼吸道鼻腔部位進行適應性計算數值模擬，還能了解鼻腔阻塞患者病因之所在，並且提供較佳的解決方案。適應性計算目的為建構出較高精確度且低計算量之網狀結構，用以模擬鼻氣道阻塞的患者鼻腔中紊流氣流的流動狀態。本文之數值模擬計算結果除了可以說明鼻氣道阻塞患者之左、右鼻道阻塞情形提供較佳的解釋外，並可以進一步顯示阻塞的區域。這個重要結果可以提供並且協助耳鼻喉科醫師未來在手術前決定鼻腔鏡手術切除區塊大小時的判定依據。上述研究除重度鼻阻塞患者之重要結果外，本文並以兩位輕度鼻阻塞患者與一位健康者做為比較組與對照組做為鼻阻塞現象之研究。在不同鼻腔中隨著呼與吸，時間變化的流動特性明顯地表示出沿著氣流流線的壓力梯度也是造成阻塞的原因之一，而不是以往學者所言僅僅是剪應力單一因素所導致的。另外，研究發現紊流氣流流線於吸氣時隨時間變化的情形顯現出在吸氣後1/3期間對噴霧顆粒沉積於鼻腔壁上是更有效的。再者，本文對呼與吸的整個過程也討論了幾種物理量場之變化情形，如流道截面積無因次分析、流量、流線、紊流動能、剪應率、沿流線之壓力梯度及渦度等。由於這些物理量場都無法以實驗方式於人體內測量得到，故必須以計算方式求出。透過這些物理量場的了解，可以對於鼻腔阻塞問題能更進一步了解，而這些均為本文重要學術貢獻之所在。適應性計算技術在時間消耗和解決方案的精確度在本文中都有令人滿意的結果。本文目前是應用MIMICS16.0×64與COMSOL5.2a軟體並配合自行開發程式進行研究分析，相信在未來計算輔助診斷並配合人工智慧的運用可以進行多的努力與研究。

關鍵字

適應性；鼻道阻塞；計算流體力學；非穩態；紊流

並列摘要

The aim of this study is to apply an algorithm of the adaptive computing to construct the mesh structure to simulate the unsteady turbulent airflow in the nasal cavity of the nasal airway obstruction (NAO) patients with the help of MIMICS 16.0×64 and COMSOL5.2a. The computing results provided superior explanations for the obstruction and revealed the region of the obstruction. The detail of the time dependent flow properties in different nasal cavities showed that the pressure gradient along the streamlines, instead of the shear stress, caused the obstruction. The pattern of unsteady streamlines showed that the positions of the vortexes vary during the respiration. Several physical properties were discussed during one respiratory cycle. The merits of the adaptive computing technique showed that the time consumption and the precision of solutions were both satisfactory. The implementation of the computer aided diagnosis can be expected with more efforts in the near future.

並列關鍵字

Adaptive ； NAO ； Computational fluid dynamics ； unsteady ； turbulent

參考文獻

1. Mygind, N., Dahl, R., 1998. Anatomy, physiology and function ofthe nasal cavities in health and disease. Adv. Drug Deliv. Rev. 29 (1/2), 3–12.

2. Elad, D., & Wolf, M. T., 2008. Air-conditioning in the human nasal cavity. Respiratory Physiology & Neurobiology, 163(1-3), 121-7.

3. Empey, D. W., 1980. Assessment of the nasal passages. British Journal of Clinical Pharmacology, 9(4), 317-9.

5. Eccles, R., 2000. Nasal airflow in health and disease. Acta oto-laryngologica, 120(5), 580-95.

6. Fraser, L., & Kelly, G., 2009. An evidence-based approach to the management of the adult with nasal obstruction. Clinical Otolaryngology,34(2), 151–155.

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適應性計算應用於人體鼻腔呼吸時空氣流動特性分析

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