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首页> 外文期刊>SIAM journal on applied dynamical systems >The role of materials selection in the urban heat island effect in dry mid-latitude climates
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The role of materials selection in the urban heat island effect in dry mid-latitude climates

机译：材料选择在城市热岛效应中的作用在干燥中际气候下

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摘要

This work investigates the role of materials selected for different urban surfaces (e.g. on building walls, roofs and pavements) in the intensity of the urban heat island (UHI) phenomenon. Three archetypal street-canyon geometries are considered, reflecting two-dimensional canyon arrays with frontal packing densities (lambda(f)) of 0.5, 0.25 and 0.125 under direct solar radiation and ground heating. The impact of radiative heat transfer in the urban environment is examined for each of the different built packing densities. A number of extreme heat scenarios were modelled in order to mimic conditions often found at low-to mid-latitudes dry climates. The investigation involved a suite of different computational fluid dynamics (CFD) simulations using the Reynolds-Averaged Navier-Stokes equations for mass and momentum coupled with the energy equation as well as using the standard k-epsilon turbulence model. Results indicate that a higher rate of ventilation within the street canyon is observed in areas with sparser built packing density. However, such higher ventilation rates were not necessarily found to be linked with lower temperatures within the canyon; this is because such sparser geometries are associated with higher heat transfer from the wider surfaces of road material under the condition of direct solar radiation and ground heating. Sparser canyon arrays corresponding to wider asphalt street roads in particular, have been found to yield substantially higher air temperatures. Additional simulations indicated that replacing asphalt road surfaces in streets with concrete roads (of different albedo or emissivity characteristics) can lead up to a similar to 5 degrees C reduction in the canyon air temperature in dry climates. It is finally concluded that an optimized selection of materials in the urban infrastructure design can lead to a more effective mitigation of the UHI phenomenon than the optimisation of the built packing density.
机译：这项工作调查了在城市热岛（UHI）现象强度的不同城市表面所选材料（例如，在建筑墙壁，屋顶和路面）中的作用。考虑了三个原型街道峡谷几何形状，反射二维峡谷阵列，前填料密度（Lambda（F））为0.5,0.25和0.125，在直接的太阳辐射和接地加热下。针对每个不同的构建密封密度检查了城市环境中辐射传热在城市环境中的影响。建模了许多极端热情景，以便模仿常见于低至中纬度干气的疾病。调查涉及使用雷诺平均Navier-Stokes方程的不同计算流体动力学（CFD）模拟的套件，用于质量和动量与能量方程以及使用标准的K-Epsilon湍流模型。结果表明，在具有稀疏构建填充密度的区域观察到街道峡谷内的更高速度。然而，这种更高的通风率并不一定被发现与峡谷内的较低温度相关联;这是因为在直接太阳辐射和地面加热的条件下，这种稀疏几何与从道路材料的较宽表面的热传递相关联。已经发现稀疏峡谷阵列对应于更广泛的沥青街道道路，得到了大大更高的空气温度。其他模拟表明，在街道上替换有混凝土道路（不同的Albedo或发射度特性）的沥青路面可以导致峡谷空气温度下的类似于5摄氏度的5摄氏度。最终得出结论，城市基础设施设计中的优化材料选择可以更有效地减缓UHI现象，而不是所建筑的包装密度的优化。

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