The Numerical Simulation Of Particles Transport Characteristic In Two-Dimensionnal Passage

As we know, airborne particles is detrimental to human health. Behavioral studies document that people spend most of their time indoors. Most of the air breathed by individuals is indoor air. So indoor air has an important effect on human health. Air travels from outdoors into a building via three main routes: mechanical ventilation through a HVAC system, natural ventilation through open doors and windows, and infiltration through gaps and cracks in the building envelope. With the development of economy, most intermediate and large commericial buildings are mechanically ventilated and, for these buildings, mechanical ventilation is usually the dominant entry path of outdoor air to the indoor environment. Consequently, particle deposition in HVAC systems influences particle concentration withing buildings. HVAC systems plays a central role in maintaining indoor air quality in large buildings and their improper functioning may lead to a variety of problems. Numerious studies have found higher rates of occupant complaints about indoor air quality and health symptoms in mechanically ventilated buildings compared to those that are naturally ventilated. Ventilation ducts can act as sinks, and in some cases as sources, for a variety of pollutants including particulate matters. When the HVAC system operates, particles and microorganisms can be realeased to air stream. So it is linked to a host of indoor air quality concerns.In order to improve HVAC hygiene, we must understand particles sources, transport and depositon. This paper first overviews now gas-particle two phases flow research status in quo and research methods. After the analysis of gas flow chacterristic, the RSM model is selected. Afte the analysis of the forces acted on the particles posed by the gas flow, and the order comparison between those forces, combining the newly research results, some forces such as Magnus force are neglected. The particle motion equation is established. In the discrete process the mostly used method, the control volume method and QUICK format are used. In the study of gas-particle flow numerical simulation, the SIMPLE arithmetic is often adopted. The relationship between the gas and particle is obtained as well as the distributions of velocity both gas and particle, or particle diameter. It is concluded that particle is always suspended in two-dimensionnal passage when the diameter is 1-5 pm at the same air speed. When the diameter becomes larger, particle may deposite in two-dimensionnal passage because of gravity. Particle may deposite in two-dimensionnal passage when the air speed becomes lower at the same diameter. But particle can't deposite in two-dimensionnal passage when the diameter belongs to 1-10μm...