Research On Smoke Spread And Control In Underground Urban Traffic Tunnel With Complex Structures

The urban underground roads become an important part of urban roads,and in the construction of urban underground roads, some special structure in the form of(bifurcation, ramps, bends) appears more and more frequently. Due to the internal structure of the city underground road has the characteristics of a bend、curve、slope and so on, making the smoke flow in the tunnel is more complex when a fire occurs, and the current flue gas flow on urban underground roads with these special section of the Characteristics is more less. Based on this, through the method of combining numerical simulation and experimental study, the tunnel and the inner curve slope smoke tunnel and control the proliferation of special techniques are studied in order to determine effective ventilation and personnel safety evacuation plan.First, through using the numerical simulation software FDS, the model and the boundary of different length is extended to simulate and study and the established model in a numerical simulation is given to the best length and reasonable boundary conditions. On the basis of the former, the establishment of a straight tunnel model of the different sources of power and straight tunnel fire tunnel width are simulated, obtaining the gas entrainment distribution along the longitudinal tunnel of different conditions, in order to provide a reference for centralized exhaust system exhaust quantity.For slope tunnel, through numerical simulation we study about the influence of flue gas diffusion properties of different tunnel slope and fire power, obtaining the tunnel longitudinal distribution of the flue gas temperature and speed. Then we use the research methods of numerical simulation and model tests, determining the critical wind speed of different slope and fire power, and the critical wind speed of the slope tunnel is fitted by the obtained wind speed values kg =1+0.0715 i.Finally, the dispersion and longitudinal smoke control of the tunnel gas are studied through numerical simulation. By changing the radius、radian and fire power of curve tunnel we study about the influence of these factors on the smoke spreading properties.The results showed that: Compared with radius, the change of the radian of the curve tunnel has a more greater influence on the smoke speading and control.