隧道竖井外流场模拟及风塔外型结构优化研究

Study on flow field simulation outside shaft and structure optimization on exterior of wind tower in tunnel

为提高长大隧道施工及运营通风过程中竖井通风效率,实现隧道节能通风。依托实际隧道工程,基于Fluent软件,选用RNG k-ε湍流模型,对无竖井风塔、圆柱风塔、矩形风塔和凸台状风塔4种结构、不同环境风速工况下的流场进行数值模拟,并对模拟结果进行交叉比对分析,提出最优化的竖井风塔结构形式。研究结果表明:采用风塔结构竖井出流量要远大于无风塔结构竖井出流量;对于不同竖井风塔外型结构,竖井出流量与环境风速关系呈多项式函数;当倾斜角为45°、圆心角为90°时,凸台结构对应竖井出流量最大,且受环境风影响波动较小,通风稳定性较好。建议竖井出口结构选用矩形或凸台状,实现对环境风的高效利用,提高竖井通风效率。

In order to improve the ventilation efficiency of shaft in the processes of construction and operation ventilation of long tunnel and realize the energy-saving ventilation of tunnel,relying on the actual tunnel project and based on the Fluent software,the RNG k-εturbulence model was selected to numerically simulate the flow field of four kinds of structures,namely,non-shaft wind tower,cylindrical wind tower,rectangular wind tower and convex platform wind tower,under different ambient wind speed conditions.The results of simulation were cross-compared and analyzed,and the optimum structure form of shaft wind tower was put forward.The results showed that the outflow rate of shaft with the wind tower structure was much larger than that without the wind tower structure.For different exterior structures of shaft wind tower,the relationship between the outflow rate of shaft and ambient wind speed presented the polynomial function.When the inclination angle was 45 degrees and the center angle was 90 degrees,the outflow rate of shaft with the convex platform structure was the largest,and the fluctuation by the influence of environmental wind was small,so the ventilation stability was better.It was suggested that the outlet structure of the shaft should be rectangular or convex platform to realize the efficient utilization of the ambient wind and improve the ventilation efficiency of shaft.