纵向风和集中排烟协同作用下隧道火灾烟气蔓延特性及分层稳定性研究
发布时间：2019-06-19 09:15
【摘要】：本文通过开展缩尺寸隧道火灾试验,结合理论分析研究了纵向通风和集中排烟协同作用下隧道火灾烟气逆流长度、烟气分层及其稳定判据,以及集中排烟模式作用下隧道火灾烟气前锋蔓延速度特征,具体的工作如下:本文通过一系列缩尺寸实验研究了集中排烟口位于火源上游时,纵向风与集中排烟协同作用对烟气逆流长度的影响。研究发现,集中排烟口处于火源上游时的逆流长度会比较小,提出了集中排烟口位于火源上游时的无量纲影响因子,建立了新的烟气逆流长度表征模型,该模型的预测结果与实验测量值吻合较好。通过实验研究了集中排烟模式作用下隧道火灾烟气前锋蔓延速率特征,将实验测量值与前人模型的结果进行综合对比分析,同时也研究了不同集中排烟速率与不同火源位置情况下隧道火灾烟气前锋蔓延速度的特征规律,弄清了集中排烟系统对烟气前锋蔓延速度的影响。在集中排烟模式作用下,考虑了Hinkley模型的预测结果与实验测得结果较为一致。实验研究了纵向风与集中排烟协同作用下隧道火灾烟气分层特征和稳定性判据。研究发现集中排烟能降低烟气层稳定性,在有集中排烟作用下,揭示了Fr数和Ri数与烟气分层稳定的定量关系:(1)当Ri2.0或Fr0.66时,浮力占据主导作用,上层烟气与下层空气呈现清晰的分层;(2)当2.0Ri1.4或0.8Fr0.66时,烟气层和空气层临界面出现不稳定现象;(3)当Ri1.4或Fr0.8时,烟气与空气剧烈掺混,不存在明显的分层现象,烟颗粒大量沉入下部空气层,烟气层已经完全失去稳定。
[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.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U458
本文编号：2502241
[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.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U458
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