Influence Of Smoke Barrier On Smoke Flow Characteristics And Smoke Exhaust Effect In The Long And Narrow Channel

With the rapid development of modern society,narrow and long channel plays a more and more important role in personnel traffic and transportation,at the same time,this also bring a huge fire risk.The characteristics of long and narrow channel structure lead to high temperature and toxic smoke in the fire which is difficult to be discharged in time,and easy to spread to the whole long and narrow space.Therefore,it is important to control the prevent fire and reduce the harm of smoke to people.Based on theoretical analysis,similarity experiment and numerical simulation methords,the smoke transport charateristcs and synergistic smoke exhaust effect of long and narrow channel fire smoke under the influence of smoke barrier are studied.With the simulation on smoke barrier height and position on the roof top temperature,longitudinal temperature distribution and smoke layer height,the maximum smoke temperature formula of ceiling is established considering 2 factors,namely,distance between smoke barrier and fire source and the height of smoke barrier.Experimental analysis of the influence of the smoke barrier on the distribution of moke temperature.The experimental results show that the influence of the smoke barrier on the longitudinal distribution of smoke was shown to be“slow attenuation” and “accelerated attenuation”,with the location of the smoke barrier as the critical position.A longitudinal attenution model of smoke flow in narrow channel with smoke barrier was established by numerical simulation method,the quantitative relationship between smoke temperature,height and location of smoke barrier was revealed.Through similar simulation experiments,with quantitative indicators for safe evacuation time,the influence of the smoke barrier on the available evacuation time was studied under the coupling condition of the smoke barrier and the wind speed.The experimental results show that the influence of longitudinal wind speed on the distribution of high temperature smoke could be reduced by smoke barrier when the wind velocity was weaker v=0m/s,no less than half a minute of the available safe evacuation time could be increased by the height of the barrier,and the effect of the height of smoke barrier on the extension of available evacuation time was gradually weakend with the increase of wind speed.A physical model of the synergistic effect of the smoke barrier and smoke exhaust was established by the mumerical simulation method,and the influence of smoke removal rate,the height of moke barrier,the distance between the smoke exhaust port and smoke barrier on characteristic parameters of the smoke and none was studied.The results show that with the increase of smoke exhaust rate,the plugholing appear in different fire rates.Smoke plugholing could be effectively prevent by increasing the height of moke barrier.The results show that with the increase of smoke exhaust rate,the plugholing apper in different fire rates.Smoke plugholing could be effectively prevent by increasing the height of smoke barrier,and the attenuation process of high temperaute in the non smoke extraction was strengthen.In comparison,the influence of smoke barrier position was little during the smoke exhaust process.When the distance between the smoke barrier and the smoke outlet is more than 1.5 times the clearance height of the tunnel,the effect of the smoke barrier can be neglected,In the actual engineering design,the movable smoke barrier should be installed within the effective distance of the smoke exhaust port,so as to improve the performance of the narrow channel type of space block and smoke exhaust.