本文關(guān)鍵詞： 高海拔 隧道火災(zāi) 熱釋放率 煙霧蔓延 溫度分布　出處：《土木工程學(xué)報》2017年08期 　論文類型：期刊論文

【摘要】：通過對海拔為4100m的高海拔隧道進(jìn)行全尺寸火災(zāi)試驗,揭示高海拔隧道火災(zāi)煙氣下沉及溫度場變化特征。試驗采用三種不同尺寸火源(0.8m~2、1.0m~2、2.0m~2),對隧道火災(zāi)煙氣蔓延特征、火區(qū)最高溫度、隧道拱頂縱向溫度分布進(jìn)行研究。試驗研究結(jié)果表明:隧道火災(zāi)試驗初期及燃燒穩(wěn)定階段,火源附近隧道上層煙氣與下層冷空氣分界明顯,火災(zāi)后期煙氣下沉嚴(yán)重;較小風(fēng)速有利于高海拔隧道小規(guī)�；馂�(zāi)煙氣逆流層縱向和垂向蔓延的控制。隧道火災(zāi)溫度場研究表明:隧道火災(zāi)溫升速率隨火源熱釋放率增大而增加;火源附近20m范圍內(nèi)溫度衰減速率較快,遠(yuǎn)火源區(qū)域隧道拱頂縱向溫度衰減較慢,趨于平緩;通過對火源上方拱頂煙氣溫度分析,發(fā)現(xiàn)隧道火災(zāi)探測采用差溫報警模式較定溫報警模式更加有效,并得出10℃/min的溫升速率可基本滿足高海拔隧道小規(guī)模火災(zāi)的初期報警;隧道拱頂縱向溫度分布規(guī)律導(dǎo)致火源遠(yuǎn)場煙氣下沉嚴(yán)重而近火源區(qū)域煙氣層化較好的特征。高海拔隧道火災(zāi)溫度分布特性試驗研究,可為高海拔隧道火災(zāi)動力特性研究提供依據(jù),為高海拔隧道人員疏散逃生提供指導(dǎo)及建議。
[Abstract]:Based on the full-scale fire test of the high-altitude tunnel at 4100m altitude, the characteristics of smoke sinking and temperature field variation of the tunnel fire are revealed. Three different sizes of fire source (0.8mm2) are used in the test. The characteristics of smoke spread in tunnel fire and the highest temperature in the fire zone are obtained. The longitudinal temperature distribution of the tunnel arch roof is studied. The experimental results show that the boundary between the upper flue gas and the lower cold air in the tunnel near the fire source is obvious at the initial stage of the tunnel fire test and the stable stage of combustion. The smoke sink seriously in the late period of fire; Small wind speed is beneficial to control the vertical and longitudinal spread of flue gas countercurrent layer in small scale fire in high altitude tunnel. The temperature field of tunnel fire shows that the temperature rise rate of tunnel fire increases with the increase of heat release rate of fire source. The temperature decay rate is faster in the range of 20m near the fire source, and the longitudinal temperature attenuation of the tunnel vault in the far fire source area is slower and tends to be gentle. Through the analysis of flue gas temperature above the fire source, it is found that the differential temperature alarm mode is more effective than the fixed temperature alarm mode in tunnel fire detection. It is concluded that the temperature rise rate of 10 鈩，

本文編號：1463652