A Study on Flow Field Characteristics and Air Purifier with Barrier Effects

Abstract

An air curtain machine is used in the entrances and exits of public places where air conditioners are used. The high-speed centrifugal or axial fan blows out the air, creating an airflow barrier to prevent air convection inside and outside, reducing air conditioning losses, and maintaining the indoor air quality by preventing dust, insects, and harmful gases from entering the room. Observation of the airflow behavior was conducted using CFD simulation, to explore whether it has a blocking effect, and the air curtain principle was applied to the air purification equipment. It is mainly composed of several rows of arrayed hole air outlets to form a multi-composite air wall. The airflow on the two sides, or below, can be blocked by the composite air wall and integrated into the main airflow, so that the air walls will not affect each other, and form a barrier effect to prevent infection. This research includes the measurement of impedance characteristics for three layers of filters made of different materials. These filters are used as the input characteristic parameters in the simulation analysis. Four scenarios are discussed, including the consultation room, hospital ward, quarantine station, and conference room. From the simulation results, it is known that when there are many people, the equipment can be set to high speed to increase the volume of air, forming a wind wall to effectively block airflow from the people in the chairs, reducing the risk of infection. Note that the rotation speed should not be too high. The air outlet equipment is susceptible to turbulent flow, which will make the airflow deviate from the expected direction and increase the possibility of mutual infection between adjacent people. Partitions can be used to block airflow to reduce the risk of infection.