行车速度对半敞开式公路隧道自然通风的影响

Influence of driving speed of semi-open city tunnel on natural ventilation

采用ANSYS中的FLUENT版块,综合考虑隧道长度和通风口面积等影响因素,在通风段布置方式相同的情况下,通过改变行车速度的快慢,进行多次对比计算,研究分析隧道静压、动压及风速的变化情况。研究结果表明:随着行车速度的增加,隧道内流场静压动压和风速等极值增大,且波动幅度增大;随着行车速度的增加,行驶车辆的影响范围逐渐增大。尤其当车辆行驶在通风段中时,通风口之间的对流作用随着车辆行驶速度的增加逐渐加大,对流场的影响范围也显著增加;在通风段布置相同时,随着行车速度的增加,自然通风效果变好。当车速大于30 km/h时,隧道内的静压、动压和风速均出现大幅度的变化,满足自然通风的要求;当行车速度小于30 km/h时候,需要进行局部机械通风。

Considering influence factors such as length of tunnel and the area of vents,a two-dimensional numerical simulation is presented in this paper by using FLUENT section of ANSYS.In the case of the same ventilation section arrangement and the change of driving speed,multiple contrast calculations were performed to analyze the changes of static pressure,dynamic pressure and wind velocity.The calculated example showed: With the increase of driving speed,the maximum of dynamic pressure and wind velocity will increase,and So as the volatility.With the increase of driving speed,influence scope of driving vehicle increase at the sare tine.When vehicle located at ventilation section,convection which between vents increases with the increase of driving speed,as well as the influence scope of the flow distribution.In the case of the same ventilation section arrangement,natural ventilation is better with the increase of driving speed.When driving speed is greater than 30 km /h,static pressure,dynamic pressure and wind velocity change greatly so that the request of natural ventilation can be satisfied; When driving speed is less than 30 km / h,sectional mechanical ventilation is needed.