Study On The Impact Of Greening Layout On The Outdoor Thermal Environment Of Chongqing Residential District In Summer

As the area of urban settlements in China grows year by year,the thermal environment of urban settlements has received widespread attention.Greening is one of the important influencing factors of outdoor thermal environment in urban residential areas,which has attracted the attention of many researchers.However,most of the current research focuses on the impact of greening rates,plant proportions and other greening quantities on the thermal environment of residential areas.There is a lack of quantitative research on the impact of different greening layouts on the thermal environment of residential areas under the same greening quantity.Therefore,this paper uses a combination of on-site measurement and numerical simulation to study the impact of the greening layout of Chongqing’s residential areas on the outdoor thermal environment,and mainly carries out the following aspects of work.First of all,through literature review,the analysis summarizes the existing research deficiencies,and establishes the research purpose and research method of this article.After on-site investigation,a residential area in Yubei District,Chongqing,which is rich in greening layout,is selected as the research object.From July to August 2018,outdoor thermal environment parameter tests are carried out on this residential area,focusing on the four types of green layouts: shrub-grass composite and tree-shrub-grass composite.Test the four thermal environment parameters of 1.5m vertical height temperature,relative humidity,wind speed and black bulb temperature near the ground,and study the change law of summer outdoor thermal environment.Secondly,compared with common CFD commercial software,the Envi-met platform is selected as the outdoor thermal environment simulation software platform to construct a residential space model.The heat and mass exchange mathematical and physical model of the outdoor thermal environment is optimized,and the measured data of the outdoor thermal environment is used as the input boundary conditions and verification basis,and the mathematical and physical model is verified.Thirdly,the study established four indicators,such as ecological greening volume ratio,fragmentation degree,planting spacing,planting orientation,as quantitative evaluation indicators of greening layout.According to 6 common outdoor greening layout methods in Chongqing’s determinant and enclosed residential areas,based on the Envimet software platform,27 greening layout examples have been established.The variation characteristics of temperature,relative humidity,wind speed,PMV value,etc.of different calculation examples are studied,and the influence of different greening layouts on the thermal environment of residential areas is explored.At the same time,the effects of ecological greening volume ratio,landscape greening fragmentation degree,tree planting spacing and planting orientation on the thermal environment quality of two types of residential areas were studied.Finally,the outdoor greening layout of a residential area in Yuzhong District,Chongqing is optimized and compared with the average outdoor temperature,PMV value and other parameters of the residential area before and after its adjustment,and it is confirmed that the thermal environment quality and thermal comfort of the residential area have been effectively improvedThrough the above research,it reveals the influence of different greening layouts on the outdoor thermal environment of Chongqing residential areas in summer,which provides a strong support for the design,planning and transformation of outdoor greening layouts in Chongqing residential areas.