Research On Ventilation Mode Of High Temperature Tunnel Face Temperature Drop Effect

The rapid development of Chinese railway construction, tunnel length, number and depth, complex geological conditions, through, linear increase, to ensure a more general. Because the increase of the depth of the tunnel and other heat (thermal and thermal effects are usually of the sandblasting workers geothermal heating, construction machinery, heat dissipation), the safety of the tunnel project, become one of the important factors of thermal damage. When construction work surface tunnel of circulating air flow can not form the only outlet, high temperature phenomenon more serious.Ventilation is the main measures to reduce the thermal damage of the tunnel construction process, as well as one of the most common ways, reasonable ventilation system can reduce the cost, the effective control of tunnel ventilation surface temperature, improve ventilation and cooling efficiency. In this paper, numerical simulation is carried out by using Fluent software, and the high temperature tunnel as the research object, simulation of the sidewall ventilation, ventilation, roof ventilation three ventilation modes, respectively, according to the different ventilation mode for high temperature tunnel surface cooling effectiveness analysis, choose a suitable for excavation of tunnel ventilation cooling of high temperature. The main research contents are as follows:1) Analysis of construction ventilation fluid theory, the excavation process of tunnel airflow temperature tunnel analysis by using the basic theory of fluid motion.2) construction of side wall ventilation, ventilation, roof ventilation mode, setting conditions, the numerical simulation is in3kinds of ventilation, contrast, and evaluate the different wind speed, different wind tube position effect of temperature. Analysis of effect of influence and the entrance surface outlet face temperature decreased the surface distance of the three factors.3) by observing the trajectories of30m flow element in the area within the tunnel face, analysis of the tunnel face temperature three ventilation effect the respective advantages of.4) set the line speed monitoring, monitoring the optimal ventilation mode, analysis, motion law of tunnel face airflow from the microcosmic angle quantization.Tunnel flow no matter what kind of sports, the media must be continuous, tracking only qualitative tracking flow micro motion, a quantitative understanding of the flow characteristics in the face, by setting the number of monitoring points, monitoring, monitoring of tunnel to the gas flow monitoring data acquisition, the monitoring data collection and analysis and a summary of the rules, general understanding of airflow movement characteristics.Surface temperature in the high temperature tunnel through the comparison of three kinds of ventilation, found vault ventilation performance good reason in the temperature control of high temperature tunnel face effect, according to the three kinds of ventilation simulation results:sidewall ventilation cooling effect is not ideal; there are mixed ventilation safety problem; vault ventilation cooling effect ideal, is worth popularizing and two from the macro and micro level, learning good control results, the conclusion can be used in the tunnel after excavation encountered in the process of using high temperature disaster, in order to provide the theory support for the construction.