| The comprehensive pipe corridor is a typical narrow and long limited space,which is equipped with a variety of municipal pipes and cables,and there are a large number of combustibles,among which the cable cabin has the highest fire incidence and the greatest risk.Once a fire breaks out in the cable cabin,it is very easy to cause a large area power outage,which seriously restricts people’s production and life.At the same time,cable combustion will produce a lot of smoke,if not discharged in time,it will bring great obstacles to fire rescue and emergency maintenance work.With the rapid development of comprehensive pipe corridor,many special structural forms have appeared due to the limitation of topography,among which the fire risk of T-type comprehensive pipe corridor is much greater than that of linear one.Therefore,it is of great significance to study the influence of fire source factors,ventilation factors and cable number factors on T-type comprehensive pipe corridor cable cabin fire.This article takes a T-type underground comprehensive pipe corridor in Hefei as the research object,establishes a cable cabin model by using PyroSim software,and studies the influence of various factors on the spread of fire smoke in the pipe corridor by analyzing the indexes such as visibility,temperature,CO concentration and so on.The conclusions are as follows:(1)The influence of the fire source location on the fire smoke is related to the ventilation scheme,and each ventilation scheme has a different maximum dangerous fire source location.The fire source distance of 50 m from the left port is the air intake of the left and right port,and the maximum dangerous fire source location of the ventilation scheme of the middle port is 50 m away from the middle port;the fire source distance of50 m from the middle port is the air intake of the left and middle ports,the air outlet of the right port and the middle port,the most dangerous fire source location of the left and right end ventilation schemes;the 150 m distance of the fire source from the left port is the air intake of the right port,and the outlet ventilation scheme of the left and middle ports is the most dangerous fire source location.The location of the maximum dangerous fire source is closest to the air inlet and farthest from the air outlet;the location of the maximum dangerous fire source is related to the location of the air outlet,when one is located on the main road of the pipe corridor,the other is located on the branch road of the pipe corridor.(2)Under different ventilation schemes,the fire source is set at the most dangerous position,the influence of outlet wind speed on the visibility of cable cabin is discussed,and the optimal outlet wind speed under different ventilation schemes is obtained.When the left and right ports enter the air,the middle port leaves the wind,and the wind speed is3m/s,the visibility of the straight section of the pipe corridor extends from 40 m to 75 m,and when the fire breaks out for 50 seconds,the visibility of the intersection has no change,which is the optimal outlet wind speed;when the left and middle ports enter,the right end exit,and the wind speed is 3m/s,the smoke of the straight section and cross section of the pipe corridor does not show countercurrent within 150 s of the fire,so it is the optimal outlet wind speed.When the middle port enters the wind,the left and right ends exit the wind,and the wind speed is 1.5m/s,the visibility of the straight section of the pipe corridor is not affected when the fire occurs for 50 seconds,and when the fire occurs for 150 s,the fire smoke of the intersection never returns to the upstream of the fire source,which is the optimal outlet wind speed;when the right port enters the air,the left and middle ports exit the wind,and the wind speed is 1.5m/s,it has the least influence on the visibility of the straight line section and the cross section,and is the optimal outlet wind speed.(3)Under different ventilation schemes,the fire source is set at the most dangerous position,the outlet wind speed is set to the optimal wind speed,and the influence of the number of cable laying(that is,the number of combustibles)on the fire smoke of the cable cabin is obtained.When the air is fed into the left and right ports and out of the middle port,the increase of the number of cable layers will shorten the time for the smoke to spread to the upstream of the fire source and increase the distance for the smoke to spread to another air inlet.When the air enters the middle port and the air comes out from the left and right ends,the temperature in the straight section of the pipe corridor is symmetrically distributed,and the high temperature area expands with the increase of the number of cable layers.When the air is in the right port and out in the left and middle ports,the length of flue gas reflux increases with the increase of the number of cable layers.Aiming at the T-shaped comprehensive pipe corridor,this article launches the influence of fire source factors,ventilation factors and combustible factors on the law of fire smoke spread,in order to provide optimization ideas for the fire protection design of the same type of comprehensive pipe corridor.Figure [65] table [10] reference [66]... |
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