Characteristics of airflow under stratum ventilation induced by fabric air dispersion system with orifices

Abstract

As a new ventilation terminal, Fabric air dispersion system (FADS) has characteristics with easy to clean and low ceiling weight load. However, it has still been unknown about the flow mechanism of air induced by FADS with orifices. In present work, the direct description method proposed in our previous work is employed to establish the numerical model of FADS with orifices under the stratum ventilation (SV), and the research is focused on the distribution of air velocity and pressure through the FADS' cavity, indoor air velocity and temperature, thermal comfort. Meanwhile, the simulation results are validated by experimental results and visualization using a smoke generator. Results demonstrate that the simulation method based on the direct description method, firstly, is feasible to precast the air characteristics under SV mode induced by FADS with orifices. Secondly, the discharge of airflow supplied by FADS with orifices is mainly dominated by the ratio of static pressure to dynamic pressure, which also determines the deflection of ejection airflow and is affected by orifice diameter. Thirdly, strategy of SV induced by FADS with orifices can supply the fresh air into occupant's breath zone with a vertical indoor air temperature difference of less than 3 K. In future work, we will experimentally investigate the characteristics of SV on FADS with orifices such as indoor air distribution, ventilation efficiency and energy saving. Research results would help optimize strategy of SV based on FADS with orifices and expand its implementation in real project.