Analysis Of Flue Gas Diffusion And Wall Flame Radiation Angle Coefficient Of Moving Fire Source In Tunnel

Due to the special environment of the tunnel,a fire will pose a huge threat to the safety of people trapped in the tunnel,and it is extremely easy to damage the tunnel structure and internal facilities.Based on the data obtained by previous experiments on the tunnel fire scale model under different ventilation conditions,the thesis calculated the vertical angle coefficient and the maximum angle coefficient of the ground near the fire source area of the tunnel fire based on the flame shape obtained.A complete angle coefficient calculation model is obtained,and the distribution law of ground angle coefficient is analyzed.In addition,the radiant heat flow calculated by the angle coefficient model is compared with the radiant heat flow measured by the experiment,which verifies the reliability of the angle coefficient calculation model.This thesis compares and verifies the dynamic grid technology,using this technology to simulate the mobile fire source of the highway tunnel,and the static,5km/h,8km/h,10km/h,15km/h,20km/h,40km/h,60km/h.Numerical simulations were carried out for the working conditions of 8 different speeds,and the changes of the smoke diffusion length S_Totalin the tunnel,the distance between the smoke diffusion front and the car fire source S₁,the highest temperature T_maxof the ceiling,and the highest temperature position S_Tmaxwith the speed of the car were obtained.As a result,compared with the smoke temperature distribution of a stationary fire source under the same environmental conditions,the law of the smoke diffusion of a mobile fire source with the vehicle speed v was obtained,and it was found that S₁continued to increase with the increase of vehicle speed,while S₂and S_Totalincreased with vehicle speed.There will be a tendency to increase first and then decrease when increasing.In addition,T_maxcontinues to decrease as the vehicle speed increases,and it is getting farther and farther from the fire source.After comprehensively analyzing the subsequent data,this article proposes to divide the mobile fire source fire into four development stages based on the change of the fire source moving speed v from small to large,namely the stationary stage,the low-speed moving stage,the medium-speed moving stage and the high-speed moving stage.And summarize and explain the law of flue gas temperature distribution in each stage.Finally,the research content of this thesis is summarized,and the follow-up development direction is prospected.