Numerical study on the smoke spread length in full-transverse ventilated UTLT-like tunnels

As is known to all, full-transverse ventilation is a good choice in the underground traffic link tunnel (UTLT). However, there is little basic research on it. When the length of the UTLT tunnel is greater than 5.2 m, the length of the smoke layer no longer follows an exponential law along with the characteristic parameter of the ratio of the cubic root of a dimensionless fire source to the dimensionless exhaust volume but still follows an exponential law with the characteristic parameter of Ri. The supplementary air is studied to determine whether the supplementary air has an impact on the spread length of the smoke layer and explores whether it can favour the distribution of the smoke layer spread. The correlation is determined between the smoke spread length and air supply, which is removed from the common divisor of air exhaust quantity through dimensional analysis. And its feasibility was verified using simulated data. This provides a preliminary impression basis for tunnel ventilation.