Evaluating single-sided natural ventilation models against full-scale idealised measurements: Impact of wind direction and turbulence
Evaluating single-sided natural ventilation models against full-scale idealised measurements: Impact of wind direction and turbulence
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DOI：
10.1016/j.buildenv.2019.106556
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发表时间：
2020-03-01
影响因子：
7.4
通讯作者：
Grimmond, C. S. B.
中科院分区：
文献类型：
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作者：
Gough, H. L.;Barlow, J. F.;Grimmond, C. S. B.
通常单面自然通风用于温带气候，以提供舒适和健康的室内环境。然而，在建成区，很难预测建筑物的自然通风率，因为它们取决于许多流动因素和开口类型。在这里，使用为期9个月的Refresh Cube Campaign （RCC）对现有模型进行评估。在一个立方体测试建筑（边长= 6 m）中，确定了一个小开口（孔隙率为1%）的基于压力的通风率。该建筑被隔离，然后在有限的交错建筑阵列中遮蔽，以模拟密集城市地区的湍流。内部和外部流量，温度和压力测量捕获了范围广泛的变异性尺度。尽管Warren和Parkins （1985, WP85）模型在30分钟平均通风量上表现最好，但所有四种模型都低估了通风量的10倍。由于风主导了堆效应，推导了WP85风驱动模式的风角函数。除了在被遮蔽的情况下具有复杂流动模式的方向外，预测大多得到了改进。首次测试了全尺寸建筑周围通风率与湍流强度（TI）之间的关系。结果表明，将TI作为乘数因子，可以对高湍流条件下（0.5 < TI < 4）单侧通风的风动模型进行改进。尽管在城市地区的遮蔽建筑中，具有高度湍流的小窗口很常见，但未来的模型开发应包括各种配置，以评估这些结果的普遍性。
Commonly single-sided natural ventilation is used in temperate climates to provide comfortable and healthy indoor environments. However, within built-up areas it is difficult to predict natural ventilation rates for buildings as they depend on many flow factors and opening type. Here, existing models are evaluated using the nine-month Refresh Cube Campaign (RCC). Pressure-based ventilation rates were determined for a small opening (1% porosity) in a cubical test building (side = 6 m). The building was isolated and then sheltered in a limited staggered building array to simulate turbulent flows in dense urban areas. Internal and external flow, temperature and pressure measurements captured a wide range of scales of variability. Although the Warren and Parkins (1985, WP85) model performed best for 30-min mean ventilation rates, all four models tested underestimated ventilation rates by a factor of 10. As wind dominated the stack effect, new coefficients were derived for the WP85 wind-driven model as a function of wind angle. Predictions were mostly improved, except for directions with complex flow patterns during the sheltered case. For the first time, the relation between ventilation rate and turbulence intensity (TI) around a full-scale building was tested. Results indicate that the wind-driven model for single-sided ventilation in highly turbulent flows (0.5 < TI < 4) can be improved by including TI as a multiplicative factor. Although small window openings with highly turbulent flows are common for sheltered buildings in urban areas, future model development should include a variety of configurations to assess the generality of these results.