Study On Optimization Design Of Wind Environment In Underground Atrium Space Based On CFD Simulation

At present,the development and utilization of underground space has become an inevitable trend for future development.However,the underground space lacks natural ventilation and the quality of the wind environment deviates.As an important underground commercial or traffic space,the atrium plays an important role in the underground space ventilation system.Therefore,this article will focus on three core issues to study the wind environment of the underground atrium space: question one,what is the current situation of the wind environment of the underground atrium space;question two,how to evaluate the wind environment of the underground atrium space;question three,how to improve the wind environment of the underground atrium space surroundings.In this paper,the field survey and questionnaire survey methods are used to study the current situation of the underground atrium wind environment,and the validity and reliability of the questionnaire are calculated using SPSS software.The following conclusions are drawn:(1)The ventilation and temperature adjustment of the underground atrium affects air conditioning The system has a high degree of dependence;(2)In the measured underground atrium,even when the air conditioning system is running,the wind speed of the underground atrium is very small,not exceeding 0.3m/s;(3)After analysis by SPSS software,the reliability coefficient of this questionnaire It is 0.84 and the validity value is 0.76.The reliability and validity of the questionnaire survey are very good.(4)66% of the respondents felt that the underground atrium was "very little wind",and 56% of the respondents felt unwell in the underground atrium;(5)More than 60% of the respondents said that enhanced ventilation makes them feel more comfortable,and respondents increased ventilation'S will is strong.Then,through literature research,a comparative analysis of the commonly used wind environment evaluation indicators at home and abroad was carried out;combined with the climatic characteristics of Xuzhou,the city where the research object is located,the evaluation criteria used in this research were selected.There are three main indicators,wind speed,air age and temperature,of which temperature is an auxiliary index used to determine the comfortable wind speed range:(1)Comfort wind speed: when the indoor temperature is lower than 20?,the comfortable wind speed range is ?1.5m/s;when indoor When the temperature is between 20?-28?,the comfortable wind speed range is 0.4-1.5m/s;when the indoor temperature is higherthan 28?,the comfortable wind speed range is 0.5-1.7m/s.(2)Air age: The air age should be less than 1800 seconds(the number of air changes per hour should not be less than twice).(3)This article focuses on the distribution of wind speed and air age over the main active height section of the underground atrium space(1.5 meters from the ground).The area where the air age on this section is less than 1800 seconds and the wind speed is within the comfort range is called the comfort area.The advantages and disadvantages of the underground atrium wind environment are evaluated by comparing the proportion of the area of ??the comfort zone on this section and the uniformity of the wind speed distribution.Finally,using the CFD simulation method,using the AIRPAK software to simulate the underground atrium wind environment under different plane aspect ratios,different areas,different air inlet layouts,wind directions,spacings and different profile forms.In this paper,according to the design and ventilation requirements,the air inlet is set at 3.5 meters from the ground.Under this condition,when the wind direction of the air inlet is inclined downward between 30°-40°,the underground atrium wind environment is the best.Through simulation research,it was found that when the aspect ratio of the atrium plane is 5:3 and 1:1(close to square),the air inlets are evenly arranged along the two long sides of the atrium and the air inlet spacing is controlled between 0.9 meters and 1.7 meters.At the time,the underground atrium space can obtain an ideal wind environment;when the aspect ratio of the atrium plane is 5:1(close to linear),the air inlets are evenly arranged along the long side of the atrium side and the air inlet spacing is controlled at 0.9 meters-1.7 Between meters,the underground atrium space can achieve an ideal wind environment.This paper also studies the underground atrium wind environment with A-shaped,V-shaped and H-shaped cross-sections.The results show that the cross-sectional shape has little effect on the underground wind environment of the underground atrium.