Calculation method and engineering application of ventilation efficiency based on release characteristics of contaminant gas

For the indoor environments with released non-passive contaminant gases, the ventilation efficiency is not only related to air distribution, but also related to the release characteristics of gas. The relationship between the ventilation efficiency of a room and the gas dispersion criterion number Π is derived through theoretical analysis, and the expression of ventilation efficiency is obtained by analysing the numerical simulation results. The research shows that Π can represent the relative magnitude of the volumetric force and the inertial force on the gaseous pollutants. The ventilation efficiency of the room with dense pollutant gas releasing can be expressed as an exponential function of Π and the height of the exhaust outlet. In engineering design, the alignment chart proposed in the article can be used to query the overall ventilation efficiency of the room and the volume ratio of flammable and explosive areas.