Abstract
Energy consumption of industrial buildings has remained continuously high, and the environmental quality requirements are also constantly improving. Only by improving industrial environmental control technology based on the transport mechanism of the pollution, can the energy consumption of industrial building environmental control be further reduced, and the environmental quality of industrial buildings can be improved as well. Therefore, after verifying the numerical simulation by experiments, this study uses a self-label method to investigate the spatio-temporal distribution of gaseous pollutants from multiple time-series sources in industrial plants with different length-span ratios. The results show that, the polluted flow in plants with different aspect ratios have different flow patterns: (i) the "Back-mixing" flow pattern occurs when the ratio of ventilation rate G and polluted flow rate at the exhaust height LP is less than 1, i.e., G/LP < 1, and (ii) the "One-way" flow pattern occurs when G/LP > 1. For plants with the "Back-mixing" pattern, the following source pollutants enter a density stratified environment induced by the retained pre-source pollutants. The flow of following source pollutants released at the same intensity as the precursor source can reach the roof, while those with low velocity and density difference may be blocked during the ascending process. The maximum height zm of the flow of the following source is related to both the initial Froude number Fr0 of the following source and the unsteady vertical density gradient of the fluid in the indoor environment dρa/dz. For plants with the "One-way" pattern, the flow from the following source enters into an environment with approximately uniform density. Under the condition of positive buoyancy, design parameters of ventilation corresponding to the vicinity of G/LP = 1 may be the optimal solution for safety and energy conservation.
