PDF(Pubmed)
Abstract：
Health problems and respiratory diseases are associated with poor indoor air ventilation. We investigated the air quality inside a classroom-laboratory where no ventilation is provided. The case of study, consisting of an internal enclosure, is located at the Escuela Técnica Superior de Edificación (ETSEM) of Madrid (Spain). The high height favours air stratification which is analysed in terms of temperature and CO2 spatial distribution. Temperature, air humidity, atmospheric pressure and CO2 concentration measurements were taken in time at three different height locations. A CFD numerical model was established to analyse air quality. Flow circulation is derived by solving full 3D Navier - Stokes governing equations, coupled with the thermal problem. The diffusion problem of the CO2 produced by the inner occupants is then derived from the kinematics solution. Three scenarios were taken into account: occupants seated (1), standing (2), half seated, half standing (3). Results clearly show the air stratification as a result of density gradient, which is in turn determined by temperature difference between the occupants and the surrounding air. Temperature prediction maximum relative error is contained to 3.5 %. As expected, CO2 concentration increases over time, reaching maximum values depending on the configuration considered and height location.
摘要：
健康问题和呼吸系统疾病与室内空气通风不良有关。我们调查了不提供通风的教室实验室内的空气质量。研究的案例,由内部外壳组成，位于马德里（西班牙）的EscuelaTécnica高级Edificación（ETSEM）。高高度有利于空气分层，根据温度和CO2空间分布进行分析。温度,空气湿度,在三个不同高度位置及时进行大气压力和CO2浓度测量。建立了CFD数值模型来分析空气质量。流动循环是通过求解完整的3DNavier-Stokes控制方程得出的，再加上热问题。然后从运动学解决方案中得出内部乘员产生的CO2的扩散问题。考虑了三种情况：就座的乘员(1)，站立（2），一半坐着，半站立（3）。结果清楚地显示了密度梯度导致的空气分层，这又是由乘客和周围空气之间的温差决定的。温度预测最大相对误差为3.5%。不出所料,CO2浓度随时间增加,根据所考虑的配置和高度位置达到最大值。
