Numerical Simulation Research On Thermal Environment Of Confined Underground Space

The closed underground space is usually not in direct contact with the outdoor atmospheric environment,the indoor thermal environment is greatly affected by the air supply parameters,and because the soil temperature around the envelope structure is lower than the outdoor ambient temperature most of the time in summer,the walls of the closed underground space are extremely high.It is prone to condensation and mildew.This paper studies the thermal environment characteristics of confined underground space and its control methods,aiming to find effective measures to prevent condensation and improve the thermal environment of confined underground space.First of all,the paper analyzes the mechanism of wall dew formation and the principle of ventilation and dehumidification,expounds the different characteristics of thermal environment of closed underground space and above ground space,calculates the annual ground temperature in Beijing area,and obtains the law between wall temperature and air dew point temperature of underground space under natural room temperature and the calculation method of wall dew formation quantity.Secondly,the reliability of the numerical simulation method is verified by experiments.Taking an underground airtight model cell in Beijing as the research object,the room temperature simulation calculation was carried out using DEST software.Numerical simulation of the airtight model cell is carried out by Fluent,and the air supply parameter range that meets the requirements of interior design parameters is obtained.Thirdly,taking a closed underground tunnel in Beijing as an example,the numerical simulation of indoor thermal environment under mechanical ventilation mode is carried out,and it is obtained that when the relative air humidity exceeds 60%in most of the summer,the inner wall temperature of the closed underground tunnel is lower than the air dew point temperature.Condensation on the wall will occur.In winter,the outdoor air temperature is lower than the indoor air temperature,and the supply air needs to be heated and then ventilated.There is no condensation in winter.Therefore,air conditioning should be used for air supply in summer.Finally,the air-conditioning air supply method is used to carry out numerical simulation on the closed underground tunnel.By comparing and optimizing the air supply parameters,the distribution law of the temperature field and humidity field in the closed underground tunnel and the ideal air supply airflow organization method and summer are obtained.Better air supply parameters.