| Due to the increase of tunnel's length and quantity, and the increase of density of road traffic, the fatalness of fire in a roadway tunnel are rising gradually. It's known from a number of fire disaster accidents that with the frequent occurrence of tunnel fire have caused enormous social and economic losses. Generally, it's the high-temperature and poisonous smoke induced from the fire that caused the damage.a suitable longitudinal ventilation system will control the temperature and the movement of the somke effectively.So the study of longitudinal ventilation control in tunnel fires will be useful for rescueing and protecting the tunnel structure from being damaged by high temperature.This paper firstly summarise the characteristics of road tunnel fires and reviewes the research status,then build a versus reasonable numerical simulation model through theoretical study of Computational Fluid Dynamics and analysis of Literatures.By using Computational Fluid Dynamics ,a Three-Dimensional Numerical Simulations of tunnel fire with longitudinal ventilation system was build and a Three-Dimensional computer fluid dynamics method was used to simulate the smoke flow in the fire. Found the critical velocity at various fire sizes and summaries the effects of gradient on tunnel on critical velocity ; Distributions of smoke spread and temperature were analyzed though a Numerical simulation of the transient on tunnel fire at 50MW and various ventilation velocity. Found a suitable ventilation control on the smoke propagation.In the paper a Numerical Simulations of tunnel fire occurs in the middle of the tunnel was also build ,found that the reaction time of mechanical ventilation is a key factor for safe evacuation of the personnel in tunnel by observeing the fire-induced smoke.The achievements of this paper enrich the analysis of ventilation control technology in tunnel fires,provides basic parameters for the research of fire-fighting and rescue system. |
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