Abstract:
Objective To investigate the distribution of particulate matter in terms of concentration and suspension time based on the measurements of spatial geometry, wind speed, particulate matter concentration, and ambient temperature of indoor places.
Methods The space of the emergency hall and the size of the medium and large facilities in the hospital were measured on site, and the number concentration of particulate matters, temperature, and wind speed in the environment were measured. The space size of the site was used to construct a model, and the environmental detection parameters were used to determine the boundary conditions of the model and verify the correctness of the model. The Lattice Boltzmann Method (LBM) was used to calculate the movement of particulate matter, and the convection-diffusion equation was used to calculate the change in the concentration of particulate matter at the outlet of the air supply system. The Discrete Phase Model was used to calculate the movement of particulate matter in the flow field.
Results Environmental detection showed that the wind speed at the outlet of the air supply system was negatively correlated with the number concentration of indoor particulate matter (P < 0.05), and the number concentration of particulate matter in the waiting area was significantly higher than that in the consulting room (P < 0.05). Simulating calculation was performed based on the mathematical model established, and the results of simulation calculation were comparable to the field measured data. Waiting crowds increased the local concentration of particulate matter. The particulate matter in the exhaled breath of the people in the waiting area could be spread to the people around within 15 seconds, and 60% of the particulate matter in the exhaled breath had a suspension time of several minutes or longer.
Conclusion Changing the spatial geometry and environmental detection parameters in the model can be used to calculate the distribution of particulate matter in different indoor places. The results of simulation calculation are comparable to the measured results, and the mathematical calculation results can support the formulation of prevention and control management measures for environmental respiratory hazards.
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