Effect of different open methods of cross-passage on the distribution of pollutants in a long tunnel ventilated by flat guides
To explore the influence of the opening mode of the cross-passage on the distribution law of pollutants in the long tunnel with the compression ventilation of the parallel guide tunnel,this paper studied the longitudinal wind speed,wind pressure loss,and the distribution law of pollutants in the tunnel under different opening modes of the cross-passage.The established tunnel model consists of 17 cross-passages,of which 5 are cross-passages for vehicles,and 12 are cross-passages for pedestrians.The cross-passages are evenly arranged.In this paper,five different ways of opening the cross-passage are considered.The results show that the longitudinal wind speed in the main tunnel is distributed in a segmented way when the horizontal guide is compressed into the ventilation system.The wind speed in the center of the tunnel is minimum,and the wind speed is greater when it is closer to the tunnel exit.When an even number of cross-passages are symmetrically opened,the longitudinal wind speed between the two cross-passages in the center of the tunnel is almost zero due to the balance of wind pressure,and the CO volume ratio cannot be diluted effectively.When an odd number of cross-passages are symmetrically opened,the wind speed in the tunnel is from the center of the tunnel to the openings on both sides.When the air volume of the horizontal ventilation is large enough,the volume ratio of CO in the tunnel can meet the requirements.In addition,when an odd number of cross-passages are symmetrically opened under the same horizontal ventilation volume,a large number of cross-passages are not conducive to diluting the CO volume ratio in the central area of the tunnel.In the tunnel model of this study,the critical ventilation volume of the three cross-passages opened symmetrically is the minimum,and the critical ventilation volume is 631 m3/s,which is not much different from the required ventilation volume calculated according to the code.Therefore,in the ventilation design of such tunnels,the ventilation volume can be calculated according to the code.The results of this study can provide a reference for the ventilation design of such tunnels.
safety and hygiene engineering technologyparallel pilot tunnelstunnel ventilationpollutants
NETL
NSTL
万方数据
维普
