Decay characteristics of expiratory aerosol in various diffuser-induced airflow patterns using large-eddy simulation

作者：Hasama Takamasa^*

来源：Building Simulation, 2013, 6(3): 225-233.

DOI：10.1007/s12273-013-0108-9

• large-eddy simulation
• expiratory aerosol
• indoor pathogen infection
• air diffuser layout
• airflow pattern
• human body

This paper presents the decay characteristics of expiratory aerosol using large-eddy simulations coupled with Lagrangian particle tracking for evaluating the prevention of pathogen infection in a typical indoor environment. Ten cases of enclosed-rooms with five different diffuser-induced airflow patterns were investigated. For particles about 10 mu m in diameter, which closely approximates the mean diameter of expiratory aerosol, the decay characteristics of each case with no obstacles proved that the most efficient case was the floor-supplied displacement type, followed by the ceiling-mounted line diffuser, floor-mounted diffuser, and ceiling-mounted square diffuser. The least effective case was the ceiling-mounted four-way cassette-type air diffuser under the same air changes per hour. However, in the situation of obstacles representing human bodies, the floor- supplied displacement type showed worse decay characteristics because of preventing the "piston flow-like" one-direction flow. On the other hand, the diffuser cases of the ceiling-mounted square type and the ceiling-mounted four-way cassette-type showed improved decay speed by exhaust and deposition. In particular, the ceiling-mounted square diffuser showed the most effective removal performance. These results imply that the flow configurations that induce small circulation caused by the inlet-outlet layout tend to improve the decay characteristics in terms of "the robust flow design" in a situation of complex flow field.

• 出版日期2013-9