- 學位論文
隔離病房呼氣污染物擴散之數值模擬分析
Numerical Simulation on the Dispersion of Exhalation Pollutants in an Isolation Room
摘要
呼吸道傳染病可經由空氣傳染將病毒由感染者散佈給其他人，當感染者咳嗽、打噴嚏或說話時會不斷的呼出飛沫微粒，這些約1 至5 μm 大小的感染性飛沫微粒若未經由適當的環境保護措施，則可輕易的散播至房內或建築物中，因此感染的病人需和其他醫院內的人員做隔離且安置在負壓隔離病房中，透過完善可靠的行政管理和環境控制策略來減少空氣傳播。本研究利用計算流體力學方法分析隔離病房中不同進、排氣口位置及污染源位置改變下(病人躺/坐姿)對病房內氣流分佈和呼氣污染物擴散的影響。研究中病房內換氣率設定為8 ACH(air change per hour)，模擬病人於一般呼吸及單次咳嗽兩種不同狀態下持續呼出帶有病原體的氣體在病房內擴散的情形，其中病人所呼出的氣體假設由空氣及二氧化碳組成，而二氧化碳則被視為帶有病原的氣體。此外考慮由病房門縫洩入的空氣氣流對病房內部氣流分佈的影響，發現進氣的氣流方向將因此受到改變，故負壓隔離病房內應儘可能的保持氣密來避免經由各種縫隙洩入的空氣氣流改變病房內原有的氣流流向。模擬結果顯示，病房中較高的排氣口位置能更有效的移除病人在不同型態下所呼出的氣態污染物。
並列摘要
Respiratory infectious diseases can spread from one infected person to other people by aerosol droplets. An infected patient continuously expels these particles when coughing, sneezing or talking. The infectious particles are easily spread in a room or building unless adequate protection or control is provided. Therefore infected patients are isolated from other individuals in hospitals and placed in negative pressure isolation rooms. This study used the computational fluid dynamics (CFD) method to investigate the airflow pattern and exhalation pollutants dispersion in an isolation room. The effects of air inlet/outlet locations and patient style of reclining/sitting have been discussed. Two cases were simulated during the study:continuous exhalation of pathogen-laden air from the patient and expulsion by a single cough. The gases exhaled by the patient were assumed to be composed of air and CO2, and the exhaled gases consisted of CO2 were considered as pathogen-laden air. The simulation results show that a higher location of exhaust outlet in the ward seems to more efficiently remove gaseous pollutants from patient exhalation.