Study on Maximum Ceiling Smoke Temperature Rise of Inclined Tunnel Wall Fires
To study the particularity of fire development law in inclined tunnel wall fire under the synergistic effect of fire buoyancy effect,wall radiant heat feedback and air entrainment restriction mechanism,using FDS to analyze the maximum ceiling smoke temperature rise and its location in inclined tunnel wall fire,considering slope and distance between the fire center and the side wall,a dimensionless prediction model of ceiling smoke maximum temperature rise and maximum temperature rise point is constructed.In inclined tunnel wall fire,the influence of the side wall limitation on the maximum temperature rise is more significant with the decrease of the distance between the fire source center and the side wall.The maximum temperature rise of the heat release rate of 2.7,4 and 5 MW tunnel wall fire reaches a maximum at 2%,1%and 0 slope respectively;As the slope continues to increase,the maximum ceiling smoke temperature rise decays exponentially with tunnel slope.Compared with the axis fire,it is closer that the distance between the maximum temperature rise point of the wall fire and the center of the fire source when the slope is less than 10%,when the slope is greater than 10%,the position of the maximum temperature rise point of the wall fire is slightly farther.With the increase of tunnel slope,air enrolling and convective heat transfer are continuously enhanced,and the flame of inclined tunnel wall fire tilts towards the upstream and side wall at the same time,which affects the force mechanism of the flame and the radiant heat feedback received by the fire source surface,the maximum temperature rise of the ceiling decreases exponentially with the increase of the slope.
inclined tunnelwall fireaxis firemaximum temperature-riseposition of maximum temperature rise point
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