Arjmandi Hamed, Amini Reza, Kashfi Mehdi, Abikenari Matthew Alexander, Davani Ashkan
MR CFD LLC. No 49, Gakhokidze Street, Isani-Samgori District, Tbilisi 0182, Georgia.
Department of Orthopedic Surgery Research Center, University of California Los Angeles, Los Angeles, California 90095, USA.
Phys Fluids (1994). 2022 Mar;34(3):037103. doi: 10.1063/5.0081291. Epub 2022 Mar 2.
The rapid spread of SARS-CoV-2 virus has overwhelmed hospitals with patients in need of intensive care, which is often limited in capacity and is generally reserved for patients with critical conditions. This has led to higher chances of infection being spread to non-COVID-19 patients and healthcare workers and an overall increased probability of cross contamination. The effects of design parameters on the performance of ventilation systems to control the spread of airborne particles in intensive care units are studied numerically. Four different cases are considered, and the spread of particles is studied. Two new criteria for the ventilation system-viz., dimensionless timescale and extraction timescale-are introduced and their performances are compared. Furthermore, an optimization process is performed to understand the effects of design variables (inlet width, velocity, and temperature) on the thermal comfort conditions (predicted mean vote, percentage of people dissatisfied, and air change effectiveness) according to suggested standard values and the relations for calculating these parameters based on the design variables are proposed. Desirability functions that are comprised of all three thermal condition parameters are used to determine the range of variables that result in thermally comfortable conditions and a maximum desirability of 0.865 is obtained. The results show that a poorly designed ventilation system acts like a perfectly stirred reactor-which enormously increases the possibilities of contamination-and that when air is injected from the ceiling and extracted from behind the patient beds, the infection spread is least probable since the particles exit the room orders of magnitude faster.
严重急性呼吸综合征冠状病毒2（SARS-CoV-2）病毒的迅速传播使医院里需要重症监护的患者数量过多，而重症监护能力往往有限，且通常只留给病情危急的患者。这导致了感染传播给非新冠肺炎患者和医护人员的几率更高，以及交叉污染的总体可能性增加。对通风系统设计参数在重症监护病房中控制空气传播颗粒扩散性能方面的影响进行了数值研究。考虑了四种不同情况，并对颗粒扩散进行了研究。引入了通风系统的两个新标准，即无量纲时间尺度和抽气时间尺度，并比较了它们的性能。此外，根据建议的标准值进行了优化过程，以了解设计变量（入口宽度、速度和温度）对热舒适条件（预测平均得分、不满意人员百分比和换气效率）的影响，并提出了基于设计变量计算这些参数的关系式。由所有三个热条件参数组成的合意函数用于确定导致热舒适条件的变量范围，并获得了0.865的最大合意度。结果表明，设计不佳的通风系统就像一个完全搅拌的反应器，这极大地增加了污染的可能性，并且当空气从天花板注入并从病床后面抽出时，感染传播的可能性最小，因为颗粒离开房间的速度要快几个数量级。
