| Being highly efficient and low in cost, heavy haul railway has frequently become the main stream of modern freight transportation. However, the combustible in the heavy haul railway tunnel, being large in volume, concentrated in distribution and high heat value, results in that the gas temperature rises quickly once a fire happened in the heavy haul railway tunnel, combined with the characters of long and narrow space for tunnel. And if effective measures have not been taken promptly, the tunnel structure may be damaged badly, which is really serious consequence to the operating of heavy haul railway. Sponsored by the innovation project fund for postgraduate education of Central South University(Grant No.2010ssxt218), the dissertation conducts a study on the characteristics of the fire caused by extremely abundant fuel in the heavy haul railway tunnel and the sealing of the fire.By theoretical analyses, numerical simulation and other methods, such aspects as the heat release rate of the fire in heavy haul railway tunnel, the spreading and the sealing of the fire has been investigated. The main content and conclusions of the study are as follows:(1) A qualitative analysis of the fire in the heavy haul railway tunnel where extremely abundant fuel is distributed, was conducted, after which the pattern of combustion under the ventilation control was determined, the formula for calculating the heat release rate of the fire in the heavy haul railway tunnel is deduced theoretically and the impact of such factors as the combustion rate and the type of the combustible as well as the tunnel opening factor on the heat release rate of the fire in the heavy haul railway tunnel is concluded.(2) With the establishment of the numerical simulation model of the fire in the heavy haul railway tunnel, by taking into consideration the power of the fire source, the position of fire source and the geometric size of the fire source, the fire in heavy haul railway tunnel is simulated, and the distribution law of temperature field in heavy haul railway tunnel is acquired. (3) Sealing and control for the fire in heavy haul railway tunnel has been investigated theoretically, and the rule how the efficiency of extinguishing by sealing is influenced by the sealing ratio, the type of the combustible and the opening factor of the tunnel has been summarized. On the basis of investigation to sealing suppression effect, the control effect to fire in heavy haul railway tunnel induced by the speed of injecting water is studied.This dissertation conducts a study on the characteristics of the fire caused by extremely abundant fuel in the heavy haul railway tunnel and the sealing suppression effect of the fire. The findings can provide a reference for practical work such as the theoretical analysis on the fire and the fire suppression in the heavy haul railway tunnel. |
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