铺面参数对近地热环境的影响研究

发布时间：2018-01-14 23:11

  本文关键词：铺面参数对近地热环境的影响研究　出处：《重庆交通大学》2015年硕士论文　论文类型：学位论文

  更多相关文章： 计算流体动力学 不同下垫面类型 材料特性 近地气温

【摘要】：城市化进程中,天然地表被人造铺面取代后,造成近地大气热环境变化,形成城市热岛效应。为了分析路面形式、铺面材料参数对近地热环境的影响规律,首先,本文将路面-近地大气视为一个相互作用的系统,进行三维数值建模,应用计算流体动力学(CFD)的非稳态方法求解控制方程。其次,通过实测数据分析了不同下垫面类型、太阳辐射强度等因素对城市近地热环境的影响,并对路-气响应模型的数值计算结果进行了有效性验证。最后,利用路-气响应模型计算并分析了太阳辐射、道路材料特性对建筑群内近地热环境的影响,并总结了不同铺面上方空气温度分布规律。主要研究结论如下:①提出了采用正反2个太阳总辐射表组成的双表测试铺面表面反射率的试验方法和以当地真太阳时11:00~13:00的平均值作为铺面反射率计算方法。②基于计算流体动力学(CFD)方法,考虑太阳短波辐射、热传导、对流换热和铺面-大气之间的有效长波辐射,建立了路-气响应的三维有限元分析模型,通过实测数据对路-气响应的三维有限元结果检验表明,该计算模型对白天时段温度数值的模拟具有较好的精度,但对夜晚时段,其模拟精度还需进一步优化。③晴朗白天时分,草地铺面上方0~60cm高度范围内,气温值波动较大。对于硬质不透水性铺面和水泥铺面来说,该高度范围值分别为0~50cm,0~100cm。针对大多数不透水性铺面,白天时段其路表上方气温分布形式可分为三种类型,分别为:日出时分型、日间时分型、傍晚时分型。④针对重庆市解放碑商圈来说,沥青材料为下垫面的路表温度场中高温区的分布面积明显多于以水泥和硬质不透水性铺面为下垫面时的高温区分布面积,且在温度值上也相对较高。由此可见,沥青路面因其较水泥、硬质不透水性铺面有较高的吸收率、比热,不适宜将其作为小区或商圈步行街的下垫面。⑤对于商圈步行道路表温度及上方气温而言,其区域内平均的温度数值随着反射率、发射率、导热系数、比热等参数的增大而减小,但温度减小幅度值随着高度的增加逐渐降低。具体结果:晴朗正午时分,铺面反射率每增加0.1,路表平均温度下降0.6℃,路表上方平均气温下降0.16℃~0.45℃。进一步分析发现,反射率变化对1.2m高度以下范围的气温值影响显著,但是对于较高处(≥1.2m高度)的气温值,其改善效果较小。综合分析各材料参数对近地气温的影响可得,通过优化材料的反射率和比热两个参数,可改善城市热岛效应。
[Abstract]:In the process of urbanization, the natural surface is replaced by artificial pavement, which results in the change of atmospheric thermal environment and the formation of urban heat island effect. In order to analyze the pavement form, the influence of pavement material parameters on the near-geothermal environment is studied. Firstly, the road-near-Earth atmosphere is regarded as an interaction system, and the three-dimensional numerical modeling is carried out, and the governing equations are solved by using the non-steady state method of computational fluid dynamics (CFDs). The effects of different underlying surface types, solar radiation intensity and other factors on the urban near-geothermal environment are analyzed through the measured data, and the validity of the numerical results of the road-gas response model is verified. The effects of solar radiation and road material characteristics on the near-geothermal environment in the building group are calculated and analyzed by using the road-gas response model. The air temperature distribution over different pavement is summarized. The main conclusions are as follows:. The results are as follows: 1. The test method of measuring the surface reflectance of pavement by using two total solar radiation meters is put forward and the local true solar time is 11: 00 / 13: 1. The mean value of 00 is used as a surface-reflectance calculation method .2 based on the computational fluid dynamics (. CFDs method. Considering the solar short-wave radiation, heat conduction, convection heat transfer and effective long-wave radiation between pavement and atmosphere, a three-dimensional finite element analysis model of road-gas response is established. The results of 3D finite element analysis show that the proposed model has good accuracy for temperature simulation in daytime period, but at night time. The simulation accuracy needs to be further optimized in the range of 0 ~ 60cm above the grass pavement during the sunny day, and the temperature fluctuates greatly. For the hard impermeable pavement and cement pavement, the simulation accuracy needs to be further optimized. The height range is 0 ~ 50 cm ~ (-1) ~ 0 ~ 100 cm 路m ~ (-1) respectively. For most impermeable surfaces, the air temperature distribution over the road surface during the daytime period can be divided into three types, namely: sunrise type. Day time, evening time 4. 4 for Chongqing Jiefangbei business district. The distribution area of the high temperature area in the road surface temperature field with asphalt material as the underlying surface is obviously larger than that of the high temperature area with cement and hard impermeable pavement as the underlying surface, and the temperature value is relatively high. Thus, it can be seen that the distribution area of the high temperature area in the road surface temperature field is higher than that in the cement and hard impermeable pavement surface. Asphalt pavement has higher absorptivity and specific heat due to its higher absorptivity than cement, so it is not suitable to use it as the underlying surface of residential area or commercial pedestrian street. 5 for the surface temperature of pedestrian road and temperature above it. The average temperature value in the region decreases with the increase of reflectivity, emissivity, thermal conductivity, specific heat and so on, but the amplitude of temperature decrease gradually with the increase of height. With the increase of surface reflectivity 0.1, the average surface temperature decreases 0.6 鈩，

本文编号：1425719