Simulation Research Of Atmospheric Thermal Environment In Urban Resident Sub-district

With the deepening of China’s reform and opening up and the rapid development of urbanization, the pressure on urban housing demand and the construction of residential quarters is increasingly developed, especially in the high-rise residential building community which is popular in recent years. However, during the construction process and operation process, the atmospheric thermal environment of the residential area may deteriorate because of the large density of building groups and the changes in the underlay surface which is a result of irrational design and planning. As a consequence, the poor residential atmospheric thermal environment will not only affect thermal comfort in residential area, but also lead to an increase of energy consumption, gathering of pollutants and other problems. Therefore, how to create a residential area with a good living environment has become a common concern for residential designers, construction builders and the occupants.In order to tackle these issues, the atmospheric thermal environment should be considered in the stage of residential district design and planning. To find out the potential threats, numerical simulation and experiments should be adopted to predict and evaluate the wind-heat environment in the residential district during the design phase. Based on the simulation and experiment result, more scientific and reasonable designs and plans could be applied to improve the outside thermal environment.In this paper, the atmospheric thermal environment in a typical residential area of Hefei will be studied by using the computer simulation software: PHOENICS. The airflow and temperature distribution of the entire district under original planning and design will be understood comprehensively and according to the simulation results the original design will be optimized. This paper aims to provide a reference for improving the planning and design of residential communities, improve the comfort and avoid gathering outdoor pollutants. To achieve this, the following aspects have been researched in detail:Firstly, based on the summaries and analysis of previous researches about urban and architectural partial atmospheric thermal environment, the importance of the optimized design to the atmospheric thermal environment in the stage of design will be shown and it is found that applying CFD simulation method is appropriate in understanding the atmospheric thermal environment of the residential building.Secondly, this paper will describe main technical principles of CFD, model theory and main parts of the calculation for the atmospheric thermal environment. Based on these theories, this research will choose a series of boundary conditions such as wind speed, outside air temperature, the mathematical model, the discrete method and the calculation rules etc. These settings will become the theoretical foundation for the CFD simulations in this research and provides theoretical and technical support.Thirdly, a residential district in Hefei will be chosen for the study. The basic situation and the meteorological conditions of this district will be initially introduced. Then the reason of choosing PHOENICS as the simulation soft will be discussed.Fourthly, according to the contents of the study we have conducted a targeted survey and a detailed introduction about the questionnaire design and the methods of data processing will be illustrated. Through the statistics and the analysis, propensity of people’s choice of the environment comfort is concluded which establishes a foundation to improve the residential atmospheric thermal environment.Fifthly, the overall simulation procedure is that: the geometry of the community is built in Sketch UP and imported into PHOENICS to conduct CFD simulations. Boundary conditions are set for summer, winter and transition season separately and the typical day in summer. After the simulations, the three-dimensional distribution of wind speed, wind speed amplification factors, airflow, air pressure and temperature parameters will be analyzed. As a result, a poor environment zone in this district is found. Based on this calculation and combined with the summaries generated in the survey, targeted improvement plan will put forward and calculate.Finally, suggestions to improve the urban residential atmospheric thermal environment are proposed to achieve the combination of theory and practice.With such a comprehensive and scientific methodology, this research can provided theoretical references for prediction and evaluation of residential outdoor atmospheric thermal environment and scientific guidance for the design and planning of the residential district. These references and guidance can be used to improve the atmospheric thermal environment and solve the deterioration of living conditions caused by urbanization.