本研究提出了一种具有吊扇和上层紫外线杀菌辐照(UR-UVGI)固定装置的室内环境的数值建模方法。数值建模采用了带有旋转参考系的稳态计算流体动力学(CFD)来模拟风扇叶片的旋转。使用速度场和残留在排气扩散器处的微生物比例的实验数据对CFD进行了验证。剩余微生物的分数表示打开UVGI时测量的空气传播微生物的浓度与关闭UVGI时测量的浓度的比率。根据验证结果,CFD模型正确地再现了吊扇旋转引起的空气运动。当环境通风率为2ACH(每小时换气)或6ACH时,CFD模型准确地预测了楼层以上2.44m路段的平均垂直速度,误差小于10%,无论吊扇的旋转方向或速度。此外,模拟结果表明,当风扇向下吹空气,转速高达235转/分时,剩余的微生物比例随环境空气交换率而增加,这与实验结果一致。此外,模拟结果准确地预测了当环境空气交换率为2ACH时剩余的微生物比例。我们得出的结论是,这种新颖的数值模型可以重现吊扇和UR-UVGI固定装置对室内环境的影响,并应有助于调查吊扇对UR-UVGI消毒效果的影响。
This study proposes a numerical modeling method for the indoor environment with ceiling fans and upper-room ultraviolet germicidal irradiation (UR-UVGI) fixtures. The numerical modeling deployed steady-state Computational Fluid Dynamics (CFD) with a rotating reference frame to simulate the rotation of fan blades. CFD was validated with experimental data of velocity field and fraction of microorganism remaining at the exhaust diffuser. The fraction of microorganism remaining represented the ratio of the concentration of airborne microorganisms measured with UVGI turned on to the one measured with UVGI turned off. According to the validation results, the CFD model correctly reproduced the air movement induced by the rotation of ceiling fan. When the ambient ventilation rate was 2 ACH (air changes per hour) or 6 ACH, the CFD model accurately predicted the average vertical speeds in the section 2.44 m above the floor with the errors less than 10%, regardless of the ceiling fan\'s rotational direction or speed. In addition, the simulation results showed that the fraction of microorganism remaining increased with the ambient air exchange rate when the fan blew air downward with a rotational speed as high as 235 rpm, which corresponded with the experimental results. Furthermore, the simulation results accurately predicted the fraction of microorganism remaining when the ambient air exchange rate was 2 ACH. We conclude that this novel numerical model can reproduce the effects of ceiling fans and UR-UVGI fixtures on indoor environment, and should aid in the investigation of the impact of ceiling fans on UR-UVGI disinfection efficacy.