本文選題：隧道火災(zāi) + 煙囪效應(yīng)　； 參考：《鄭州大學(xué)》2015年碩士論文

【摘要】：隨著人們對交通便利性越來越高的要求,隧道成為了緩解交通壓力,縮短通行里程的有效方式之一。但是,近年來頻繁發(fā)生的隧道火災(zāi)警示人們,如果不有效控制隧道內(nèi)火災(zāi)的發(fā)展,將造成巨大的財產(chǎn)損失和人員傷亡。隧道狹長的內(nèi)部結(jié)構(gòu)和空間密閉性導(dǎo)致火災(zāi)發(fā)生后大量有毒高溫氣體聚積在隧道內(nèi),對后期救援工作帶來一定困難。因此,研究隧道火災(zāi)發(fā)展特性和防排煙效果具有重要意義。本文根據(jù)相似原理建立了1:10小尺寸實驗臺,研究豎井對隧道火災(zāi)發(fā)展特性的影響,主要包括火源功率、頂棚下最高溫度和煙氣縱向溫度分布。分別建立了無量綱火源功率、無量綱頂棚下最高溫度隨火源與豎井距離、豎井高度變化的預(yù)測模型。研究結(jié)果表明,無量綱火源功率隨著火源距豎井距離的增大呈指數(shù)衰減。豎井對火源功率的影響可以分為兩個區(qū)域:Ⅰ區(qū)為近豎井區(qū);Ⅱ區(qū)為遠(yuǎn)豎井區(qū)。Ⅰ區(qū)的大小隨豎井高度呈線性增長,符合公式**S?3.03?1.5H。在Ⅰ區(qū):無量綱火源功率、無量綱頂棚下最高溫度隨豎井高度增加呈線性增長且斜率較大,當(dāng)*S?1時,火源功率是無豎井工況的1.35倍。在Ⅱ區(qū):無量綱火源功率、無量綱頂棚下最高溫度隨豎井高度增加變化不大。豎井的煙囪效應(yīng)對隧道內(nèi)煙氣縱向分布有降溫作用,下游煙氣的溫度降與S*符合指數(shù)衰減關(guān)系。通過變化豎井高度和火源距豎井距離,研究了豎井的排煙效果。結(jié)果表明,隨著遠(yuǎn)離火源,到達(dá)豎井附近的煙氣水平慣性力逐漸減小,導(dǎo)致豎井排出的煙氣質(zhì)量流率線性減小。豎井較低時,煙氣受到的煙囪效應(yīng)相對較小,熱煙氣主要在水平慣性力作用下從豎井口下游排出,排煙效率較低。豎井達(dá)到一定高度時,豎井高度大于了回流區(qū)域,此時較強(qiáng)的煙囪效應(yīng)減弱了由于邊界層導(dǎo)致的大尺度漩渦對排煙效果的影響,排煙煙質(zhì)量流率線性增大,排煙效率增強(qiáng)。
[Abstract]:With the increasing demand of traffic convenience, tunnel has become one of the effective ways to relieve traffic pressure and shorten mileage. However, the frequent tunnel fires in recent years warn people that if the development of fire in the tunnel is not effectively controlled, it will cause huge property losses and casualties. The long and narrow internal structure and space sealing of the tunnel lead to the accumulation of a large number of toxic and high temperature gases in the tunnel after the fire, which brings some difficulties to the rescue work in the later stage. Therefore, it is of great significance to study the characteristics of tunnel fire development and smoke control. Based on the principle of similarity, a 1:10 small scale experimental bench is established to study the influence of shaft on tunnel fire development characteristics, including fire source power, maximum temperature under ceiling and longitudinal temperature distribution of flue gas. The prediction models of dimensionless fire source power and the maximum temperature under the dimensionless ceiling with the distance between the fire source and the shaft and the height of the shaft are established respectively. The results show that the dimensionless fire source power decreases exponentially with the increase of the distance from the fire source to the shaft. The influence of shaft on the power of fire source can be divided into two regions: area 鈪，

本文編號：1887752