Research Of Indoor Air Stability 's Effects On Interactive Process Of Breathing

Interactive process of breathing of indoor environment has a great influence on the indoor air quality and the control of indoor pollutants, which will directly influence the health condition of people who works and lives indoor. In order to understand how indoor air stability affects human interactive process of breathing, the effects of unstable condition, neutral condition, and stable condition on the respiratory airflow have been discussed in this paper, and the causes of these effects have been analyzed.The experiments of indoor air stability have been carried out in this study. Through different heating methods, three different indoor air temperature gradients have been created in the laboratory. In order to achieve the purpose of visualization study of respiratory airflow, exhaling manikin, inhaling manikin and smoke generator have been used in this study. Trajectories of respiratory airflow have been photographed to analyze the differences. In addition, a full-scale model has been built according to the laboratory, using computational fluid dynamics methods. CO 2 has been chosen as the tracer gas to show the pollutants movement. Respiratory airflow patterns have been studied b y analyzing the CO2 concentration. And the experimental results and simulation results have been compared to find the differences.The study shows that, when gravity is not exists, the simulation results of unstable condition, neutral condition, and stable condition are found the same. This result indicates that indoor air stability only can exist when the existence of gravity as a prerequisite. When the acceleration of gravity is-9.8 m/s2, the experimental results are in agreement with the simulation results. Unstable condition has a great influence to make the turbulence of respiratory airflow more intensity in the vertical directio n. Entrainment effect of mainstream has been enhanced, and the pollutant diffusion range is bigger. Because of the effects of buoyancy, the upward movement of the respiratory mainstream has been enhanced, which makes the pollutants difficult to stay in the breathing area. On the contrary, stable condition has a great influence to inhibit the turbulence of respiratory airflow in vertical direction, which makes the mixture of mainstream and ambient air more difficult. Pollutant diffusion area is limited, the concentration of pollutant is much higher, and most of the pollutants are inhaled by people. The results of neutral condition are between unstable condition and stable condition.Therefore, indoor air stability has significant influence on the i nteractive process of breathing, and it also important for eliminating indoor air pollutants more effectively, improving indoor air quality and designing more reasonable ventilation systems.