Study On Fire Numerical Simulation And CPS Ventilation And Smoke Exhaustion System In Large Section Tunnel

Tunnel fires bring great challenges to the long-term safe operation of tunnels,disaster prevention and rescue.At the same time,the development process and laws of tunnel fires are closely related to the geometric dimensions of the tunnel.Underwater super-long highway tunnels are super wide and flat,with special geological conditions and complicated surrounding road networks.Once a fire occurs,it is difficult for people to evacuation and rescue,and the consequences are particularly serious.In addition,long and large tunnels usually have large and complicated ventilation systems,and the intelligence and information level of operating ventilation and smoke exhaustion systems needs to be improved.At present,there are few relevant norms and standards regarding the long and large underwater tunnels,and the research on the tunnel safety operation system is being carried out gradually.Therefore,the thesis carried out the numerical simulation of the large section underwater tunnel fire and the research of the ventilation and smoke exhaustion system.The main research contents are as follows:(1)A numerical calculation model of tunnel fire was established by FDS,the distribution law of temperature field and the spread law of smoke field in the tunnel under different fire scales and different longitudinal wind speeds were studied,and the time-varying law,spatial distribution state and maximum temperature were quantitatively analyzed.The law of temperature change,analysis of smoke spread characteristics under different fire scales,clarification of the critical wind speeds,quantification of the relationship between smoke layer height,visibility,and CO distribution in the fire site and longitudinal wind speeds.(2)A numerical calculation model of tunnel fire with jet fans was established by FDS.The effects of layout parameters on the temperature field and velocity field were evaluated,and fan installation heights,lateral spacings or longitudinal spacings and the velocity of fire downstream were quantitatively analyzed,and a multi-fan combination opening scheme meets the critical wind speed is given.(3)The feasibility of applying the CPS(Cyber Physical System)to tunnel ventilation and smoke exhaustion was analyzed,and combined with the control requirements of ventilation and smoke exhaustion of underwater long tunnels,a tunnel ventilation and smoke exhaustion system based on CPS is designed,dividing the longitudinal direction of smoke exhaust section,a ventilation and smoke exhaust control strategy was formulated.In summary,this paper studied the distribution laws of the temperature field and the spread law of smoke fields for large section tunnel fire,analyzed the influence of layout parameters of jet fans on tunnel ventilation and smoke exhaust,designed a CPS-oriented underwater tunnel ventilation and smoke exhaust system,and the research conclusions can provide a theoretical reference for underwater tunnel fire research and the design of ventilation and smoke exhaust system design,and can also provide application reference for the design of ventilation and smoke exhaust in similar projects.