Abstract: Abstract: In order to explore the coupling change mechanism of the flue gas and the wind network structure of the angle-connected pipe network during the fire period, based on the FDS numerical simulation technology, the ignition point is set at the angle-connected branch, and 12 kinds of working conditions of the outlet wind speed are given, combined with the smoke spread model, temperature attenuation model and maximum temperature model in single tunnel, the coupling relationship of wind speed-flue gas and wind speed-temperature in the angle-connected pipe network was obtained. The results show that the Froude number can better explain the smoke spreading behavior of the angle-connected pipe network. The angle-connected branch ceiling temperature attenuation law is exponential, which is related to the value of the St number. The maximum temperature of the angle-connected branch with the change of wind speed increase and decrease. The smoke retreat distance and wind speed in the left and right passages are in logarithmic relationship, and the critical wind speeds are 2.98 m/s and 4.32 m/s respectively. The temperature attenuation rate at the right associated point is greater than that at the left associated point.

Key words: Key words: diagonal pipe network, smoke layer height, temperature attenuation, smoke retrograde, FDS