發(fā)布時間：2019-06-19 09:15

【摘要】：本文通過開展縮尺寸隧道火災(zāi)試驗,結(jié)合理論分析研究了縱向通風和集中排煙協(xié)同作用下隧道火災(zāi)煙氣逆流長度、煙氣分層及其穩(wěn)定判據(jù),以及集中排煙模式作用下隧道火災(zāi)煙氣前鋒蔓延速度特征,具體的工作如下:本文通過一系列縮尺寸實驗研究了集中排煙口位于火源上游時,縱向風與集中排煙協(xié)同作用對煙氣逆流長度的影響。研究發(fā)現(xiàn),集中排煙口處于火源上游時的逆流長度會比較小,提出了集中排煙口位于火源上游時的無量綱影響因子,建立了新的煙氣逆流長度表征模型,該模型的預(yù)測結(jié)果與實驗測量值吻合較好。通過實驗研究了集中排煙模式作用下隧道火災(zāi)煙氣前鋒蔓延速率特征,將實驗測量值與前人模型的結(jié)果進行綜合對比分析,同時也研究了不同集中排煙速率與不同火源位置情況下隧道火災(zāi)煙氣前鋒蔓延速度的特征規(guī)律,弄清了集中排煙系統(tǒng)對煙氣前鋒蔓延速度的影響。在集中排煙模式作用下,考慮了Hinkley模型的預(yù)測結(jié)果與實驗測得結(jié)果較為一致。實驗研究了縱向風與集中排煙協(xié)同作用下隧道火災(zāi)煙氣分層特征和穩(wěn)定性判據(jù)。研究發(fā)現(xiàn)集中排煙能降低煙氣層穩(wěn)定性,在有集中排煙作用下,揭示了Fr數(shù)和Ri數(shù)與煙氣分層穩(wěn)定的定量關(guān)系:(1)當Ri2.0或Fr0.66時,浮力占據(jù)主導(dǎo)作用,上層煙氣與下層空氣呈現(xiàn)清晰的分層;(2)當2.0Ri1.4或0.8Fr0.66時,煙氣層和空氣層臨界面出現(xiàn)不穩(wěn)定現(xiàn)象;(3)當Ri1.4或Fr0.8時,煙氣與空氣劇烈摻混,不存在明顯的分層現(xiàn)象,煙顆粒大量沉入下部空氣層,煙氣層已經(jīng)完全失去穩(wěn)定。
[Abstract]:In this paper, by carrying out the fire test of the size tunnel, the back-flow length of the tunnel fire, the smoke stratification and the stability criterion of the tunnel fire smoke under the co-operation of the longitudinal ventilation and the centralized smoke exhaust are studied in combination with the theoretical analysis, and the characteristic of the propagation speed of the tunnel fire flue gas forward under the action of the centralized smoke exhaust mode is studied. The concrete work is as follows: this paper studies the effect of the coordinated action of the longitudinal wind and the centralized smoke exhaust on the length of the flue gas in the upstream of the fire source through a series of scaling experiments. It is found that the counter-current length of the centralized smoke exhaust port in the upstream of the fire source is relatively small, and the dimensionless influence factor of the centralized smoke exhaust port at the upstream of the fire source is put forward, and a new flow-flow length characterization model of the flue gas is established, and the prediction result of the model is in good agreement with the experimental measurement value. In that experiment, the characteristic of the propagation velocity of the fire smoke in the tunnel fire under the action of the concentrated smoke exhaust mode is studied, and the experimental measurement value is compared with the result of the previous model. At the same time, the characteristic law of the velocity of the fire smoke in the tunnel fire at different concentration of smoke exhaust rate and the position of different fire sources is also studied, and the influence of the centralized smoke exhaust system on the speed of the spread of the smoke is ascertained. The results of the prediction of the Hinkley model are consistent with the experimental results under the effect of the centralized smoke exhaust mode. The characteristics and stability criteria of tunnel fire smoke under the synergistic effect of longitudinal wind and concentrated smoke exhaust are studied in this paper. In this paper, the quantitative relation between the number of Fr and the number of Ri and the layer stability of the flue gas is revealed under the effect of centralized smoke exhaust. (1) When the R2.0 or Fr0.66, the buoyancy takes the leading role, and the upper flue gas and the lower layer of air are clearly layered; (2) When 2.0 Ri1.4 or 0.8Fr0.66, the critical surface of the flue gas layer and the air layer is unstable; (3) when the Ri1.4 or Fr0.8, the flue gas and the air are mixed vigorously, there is no obvious layering phenomenon, and the smoke particles are sunk into the lower air layer, and the smoke layer has completely lost the stability.
【學位授予單位】：合肥工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2017
【分類號】：U458

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本文編號：2502241