Operating room ventilation is quite important to protect patients from infection risk inside a surgical field. The laminar flow units (LAF) used in these applications contribute to removal of pathogen particles from the operation area by creating a protection zone on the surgical field. In this study, effect of LAF diffuse size on airflow and particle distribution in an operating room is investigated using computational fluid dynamics (CFD). Three different diffuser sizes (1.8 m x 2.4 m, 2.4 m x 2.4 m, 3.2 m x 3.2 m) and three different particle diameters (5 µm, 10 µm, 20 µm) are examined. In the modeling of airflow and particle motion, the Realizable k-ε turbulence model and Lagrangian approach are used, respectively. The distributions of airflow and particles originated from the surgical team are analysed. Also, the air change efficiency is predicted as for the entire operating room and for the breathing zone. The results reveal that the LAF diffuser size has a decisive role in air velocity and contaminant distribution in the operating room. It is seen that the amount of particles deposited on the operating table could be reduced up to 73% by increasing the diffuser size.

手术室通风对于保护患者免受手术区域内的感染风险非常重要。在这些应用中使用的层流单元（LAF）通过在手术区域上形成保护区，有助于从手术区域去除病原体颗粒。在这项研究中，使用计算流体力学（CFD）研究了LAF扩散尺寸对手术室中气流和颗粒分布的影响。检查了三种不同的扩散器尺寸（1.8 mx 2.4 m，2.4 mx 2.4 m，3.2 mx 3.2 m）和三种不同的粒径（5 µm，10 µm，20 µm）。在气流和粒子运动的建模中，分别使用了可实现的k-ε湍流模型和拉格朗日方法。分析了来自手术团队的气流和微粒的分布。还，预测整个手术室和呼吸区域的换气效率。结果表明，LAF扩散器的尺寸对手术室中的空气速度和污染物分布具有决定性的作用。可以看出，通过增加扩散器的尺寸，可以将沉积在手术台上的颗粒数量减少多达73％。