Analysis of experimental data on the effect of fire source elevation on fire and smoke dynamics and the critical velocit...
status: published
Control of fire smokes in road tunnels equipped with mechanical ventilation systems
In this thesis, fires in road tunnels with longitudinal and transverse ventilation systems are investigated numerically and experimentally. The fire smoke is simulated as a buoyant plume obtained by injecting a mixture of air and helium into ambient air. With this simplified representation, the radiation and the heat losses at the walls are not tak...
A theoretical and experimental study of flame length under a tunnel ceiling
Published in Journal of Thermal Analysis and Calorimetry
Tests in model tunnel (1:20) were performed and analyzed in order to study the effects of tunnel cross section (width and height) together with ventilation velocity on ceiling flame length in case of large heat release rate. Test results show that in tests with the same fuel and ventilation velocity, the flame length tends to decrease with increasi...
A Study of the Critical Velocity of Smoke Bifurcation Flow in Tunnel with Longitudinal Ventilation
Published in Fire Technology
Small longitudinal velocity cannot prevent backlayering in tunnel fire, while excessive longitudinal velocity will destroy stratification of smoke layer and lead to bifurcation flow. As smoke bifurcation flow proceeds, the longitudinal flow is divided into two streams and flow along both sidewalls of the tunnel ceiling. The critical velocity of bif...
Experimental Study on the Influence of Different Transverse Fire Locations on the Critical Longitudinal Ventilation Velo...
Published in Fire Technology
A set of fire experiments were conducted in a small-scale tunnel of length 8 m, width 1 m and height 0.5 m, to investigate the influence of different transverse fire locations on the critical longitudinal ventilation velocity for suppressing the smoke backflow in tunnel fire. Six pool sizes were separately used in the experiment, and the burning ra...
Performance evaluation of alternative tunnel longitudinal ventilation systems using two inclined jets
Published in Tunnelling and Underground Space Technology incorporating Trenchless Technology Research
This paper advances a novel design for providing longitudinal ventilation which utilizes the principle of induction while ensuring energy efficiency and allowing a better use of space. The induced longitudinal flow is generated by two inclined jets located about the midpoint between the floor and the ceiling allowing jets to entrain stagnant air fr...
Numerical Analysis for Reduced-scale Road Tunnel Model Equipped with Axial Jet Fan Ventilation System
Published in Energy Procedia
In this paper a preliminary tridimensional CFD analysis is carried out for a future realization of a reduced-scale road tunnel experimental apparatus of 1/50 equipped with different impulsive fans, traditional and alternative. The alternative jet fan is provided of inlet/outlet sections inclined at a fixed pitch angle (α=6°) toward the tunnel floor...
