Santamaría Bertolín Luis, Fernández Oro Jesus Manuel, Argüelles Díaz Katia, Galdo Vega Mónica, Velarde-Suárez Sandra, Del Valle María Elena, Fernández Luis Joaquín
Fluid Mechanics Area, Department of Energy, University of Oviedo, C/ Wifredo Ricart, s/n, Gijón, Asturias, 33204, Spain.
TK Elevator Innovation Center, La Laboral, C/ Luis Moya Blanco 261, Gijón, Asturias, 33203, Spain.
J Build Eng. 2023 Jan 1;63:105466. doi: 10.1016/j.jobe.2022.105466. Epub 2022 Nov 2.
Ventilation in confined spaces is essential to reduce the airborne transmission of viruses responsible for respiratory diseases such as COVID-19. Mechanical ventilation using purifiers is an interesting solution for elevator cabins to reduce the risk of infection and improve the air quality. In this work, the optimal position and blowing direction of these devices to maximize ventilation and minimize the residence time of the air inside two cabins (large and small) is studied. Special attention is devoted to idle periods when the cabin is not used by the passengers, in order to keep the cabin ambient safe and clean, avoiding that the trapped air in the cabin (after its use) could suppose a reservoir for contaminants. CFD numerical models of two typical cabin geometries, including the discretization of small slots and grilles for infiltration, have been developed. A full 3D URANS approach with a k-epsilon RNG turbulence model and a non-reactive scalar to compute the mean age of air (MAA) was employed. The CFD results have been also validated with experimental measurements from a home-made 1:4 small-scale mock-up. The optimal position of the purifier is on the larger sidewall of the cabins for a downward blowing direction (case 1 of the database). Flow rates in the range of 0.4-0.6 m/min, depending on the size of the cabin, are sufficient to assure a correct ventilation. Upward blowing may be preferable only if interaction of the jet core with the ceiling or other flow deflecting elements are found. In general, the contribution of infiltrations (reaching values of up to 10%), and how these secondary flows interact with the main flow pattern driven by the purifier, is relevant and not considered previously in the literature. Though an optimal position can improve ventilation considerably, it has been proven that a good choice of the purification flow rate is more critical to ensure an adequate air renewal.
在密闭空间中进行通风对于减少导致 COVID - 19 等呼吸道疾病的病毒的空气传播至关重要。使用净化器的机械通风是电梯轿厢降低感染风险和改善空气质量的一个有趣解决方案。在这项工作中，研究了这些设备的最佳位置和吹风方向，以在两个轿厢（大轿厢和小轿厢）内实现通风最大化并使空气停留时间最小化。特别关注轿厢未被乘客使用的闲置时段，以便保持轿厢环境安全清洁，避免轿厢内滞留的空气（使用后）成为污染物的储存源。已经开发了两种典型轿厢几何形状的计算流体动力学（CFD）数值模型，包括用于渗透的小狭缝和格栅的离散化。采用了带有 k - ε 重整化群（RNG）湍流模型和非反应标量来计算空气平均年龄（MAA）的全三维非稳态雷诺平均纳维 - 斯托克斯（URANS）方法。CFD 结果也通过自制 1:4 小比例模型的实验测量进行了验证。净化器的最佳位置是在轿厢较大的侧壁上，吹风方向向下（数据库中的情况 1）。根据轿厢大小，流速在 0.4 - 0.6 米/分钟范围内足以确保正确通风。仅当发现射流核心与天花板或其他气流偏转元件相互作用时，向上吹风可能更可取。一般来说，渗透的贡献（可达 10%）以及这些二次流如何与净化器驱动的主流模式相互作用是相关的，且此前在文献中未被考虑。尽管最佳位置可以显著改善通风，但已证明选择合适的净化流速对于确保充足的空气更新更为关键。
