为探究蓝绿空间的协同冷却效应,运用计算流体动力学(computational fluid dynamics,CFD)方法将标准k-e(湍动能-耗散率)模型、DO(discrete ordinates)太阳辐射模型及组分输运模型相结合,分析了太阳辐射下建筑形态和街区配置对峡谷热湿环境的影响,考虑了不同辐射时间(1 100地方太阳时(local solar time,LST)背风墙加热、1 300LST迎风墙加热)、不同建筑形态(均匀形、凹形、凸形)、不同街区配置(无蓝绿空间、有蓝绿空间).结果显示:太阳辐射下,行人层空气温升最高为5℃;峡谷中心和外侧背风墙小涡旋区域在无蓝绿空间时温度更高,在有蓝绿空间时温度更低、湿度更高,蓝绿空间的加入可降低平均温度4℃,降低平均生理等效温度(physiological equivalent temperature,PET)2℃;3种街区形态中,凹形街区对应更大的风速和更低的温度,其热湿环境最好,凸形街区对应更低的风速,其热湿环境最差.结果表明:蓝绿空间协同冷却效应对城市热湿环境是积极的,通过改变街区布局可以最大化其协同冷却效应.
Analysis of synergistic cooling effect of urban blue-green spaces under solar radiation
In order to investigate the synergistic cooling effect of the blue-green spaces,the standard k-e(turbulent kinetic energy-dissipation rate)model,discrete ordinates(DO)solar radiation model and component transport model were combined by computational fluid dynamics(CFD)to analyze the influence of building morphology and block configurations on the thermal and humid environment of canyon under solar radiation.Different radiation times(1 100 local solar time(LST)heating for leeward wall,1 300 LST heating for windward wall),different building forms(uniform,concave,convex types),and different neighborhood configurations(with and without blue-green space)were considered.The results show that the maximum temperature rise in the pedestrian airspace under solar radiation is 5℃,the temperature in the center of the canyon and the small vortex area of the outer leeward wall is higher when there is no blue-green space,and the temperature is lower and humidity is higher when there is a blue-green space.The addition of blue-green space can reduce the average temperature by up to 4℃,and reduce the average physiological equivalent temperature(PET)by up to 2℃.Among the three types of blocks,concave blocks correspond to higher wind speed and lower temperature,and have the best thermal and humidity environments,while convex blocks correspond to lower wind speeds and have the worst thermal and humidity environments.The results show that the blue-green space synergistic cooling effect is extremely positive to the urban thermal and humidity environment,and the synergistic cooling effect can be maximized by changing the block layout.
blue-green spacessynergistic cooling effectCFDthermal and humid environment
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