Numerical Simulation Research On Features Of Ceiling Jet In Tunnel Near Fire With Longitudinal Wind

Since the rapid development of the economic, transportation has developed a lot. As a dominant position, traffic tunnels bring convenience and thrift, but also bring some new hidden safety troubles. Due to the uniqueness of the tunnel structure, it has relatively closed long and narrow channels and cross-sectional area. In general, the tunnel fire is a small probability event. Once it spread, the poisonous and harmful gas and high temperature hot flue gas from incomplete combustion often lead to a serious safety accident of group injury or die. Therefore, research on tunnel fire smoke temperature and flow properties is of great significance for tunnel fire.In view of the domestic and foreign existing research from different size of the field test of conclusion, Based on the research about tunnel roof structure fire protection and fire plume and smoke rise in the tunnel ceiling, an experience formula of highest flue gas temperature was predicted by Kurioka, the smoke air longitudinal attenuation law by Hu Longhua, Li Liming, Yi Liang put forward the heat of combustion resistance effect. based on the comparison and analysis of the existing theory, The paper use the computational fluid dynamic software FDS to simulate the different distribution characteristics of upstream and downstream of the tunnel fire area. The paper use two kinds of fire power, seven kinds of ventilation, the wind speed and height of different fire under simulated conditions to compare with existing empirical formula.From the existing research which set fire to the premise of the ground fire, the article set the fire source position higher innovative, the fire plume directly act on the top of the tunnel roof. Revised fitting and using empirical formula, his paper analyzes on the position of the maximum temperature of migration and numerical different attenuation, high temperature flue gas layer under the longitudinal ventilation, fire flame under the effect of longitudinal ventilation combustion offset distance of the disturbance of downstream. The results show, In the simulation verify the ground fire, use improvement of formula from Kurioka and existing study simulation validation, there are more in line with the results; In the contrast of the longitudinal attenuation coefficient of empirical formula calculation and simulation results, the calculation error of numerical simulation of the temperature obtained from formula is bigger, we need to analyze the effect of parameter definition correction applied conditions.Based on theory analysis, numerical simulation, the method of comparative study research on physical characteristics of tunnel fire smo ke flow, it also offer the further help to analyze the tunnel fire combustion characteristics.