Research On Natural Ventilation Technology Of Urban Underground Space In Guangzhou

Natural ventilation is the key tactic of sustainable building design. Bring the natural wind into underground space of the cities could contribute a great in improving air quality and energy saving. Based on investigation study, site measurements and CFD numerical simulation have been employed to analyze and study a certain underground space natural ventilation (USNV) in Guangzhou, so as to instruct the application of natural ventilation in urban underground space. The main work of this dissertation could be stated as follows:1. Analyzed the evaluation index of USNV, supposed air exchange rate as evaluation index of USNV, and took the lowest air exchange rate to simplify the evaluation process. Based on conforming people flow density and the lowest fresh air exchange rate, the lowest air exchange rate could be calculated by simplified formula.2. Introduced the natural ventilation measurement of USNV. Firstly, give a brief description of the site environment, measuring instrument, measuring scope and accuracy. Secondly, introduce the experimental scheme and the process. Lastly, analyze the measured data, found that natural wind flow into and out the metro station within the daily operation period which could satisfy the lowest fresh air requirement. If metro station assisted by artificial ventilation, the measured wind data is relative stable and fresh air rate is enough. If metro station operating without artificial ventilation, the measured data shows the natural ventilation is limited but could meet the lowest fresh air requirement, except that people flow density is too bigger.3. Numerically simulated the USNV,established mathematical model and brief physical model. Compare and verify the boundary condition setting of simulation, figure out the boundary condition setting method of USNV. Through analysis of simulation results, found that fresh air flow is weak due to the influences of crowded blocks and the poor inlet and outlet setting.4.Analysing the influencing factors for natural ventilation of underground space , based on numerical modle of Subway station , the author made improvement simulations through the setting of vents and courtyards . Further, studied the effect of natural ventilation after improvement and considered the results of research on improvements can guide the design of natural ventilation in underground space.