铁路隧道压入式通风流场分析及施工参数优化

台阶法具有适应性强、应用较广泛等的优势,但鉴于台阶法施工隧道有限空间结构的特殊性,对台阶法施工铁路隧道压入式通风流场进行研究分析,并对隧道通风施工参数进行优化.依托兴泉铁路某隧道,采用流体力学分析软件FLUENT,针对台阶法施工隧道压入式通风风管位置、风管出风口距工作面距离、台阶长度及台阶高度等因素对流场的影响进行数值模拟,分析不同工况下的流场特征并进行相应参数优化.结果表明:隧道通风在台阶法施工隧道中是有限空间的受限贴附射流,并且风管侧部布置更有利于空气流通,同时发现台阶的存在在一定程度上不利于洞内空气的流通,风管出风口距工作面的距离、台阶长度和台阶高度之间存在优化组合.

Analysis of Pressure Ventilation Flow Field in Railway Tunnel and Optimization of Construction Parameters

In view of the particularity of the limited space structure of the step construction tunnel, the fluid mechanics analysis software FLUENT was used to determine the location of the press-fit ventilation duct, the distance from the air outlet of the duct to the working surface, the length and height of the step ,and then numerically simulated the influence of the flow field, analyzed the flow field under the influence of various factors and optimized the corresponding parameters. The results show that: 1) the stepped construction tunnel press-in ventilation is a limited attached jet in a limited space; 2) the air duct is located on the side to facilitate the timely circulation of air in the limited construction space; 3) when the step height reaches the air duct and When the air outlet is at a certain distance, the presence of the steps on the tunnel has a certain lifting effect on the jet; 4) The smaller the distance between the air outlet and the working surface of the upper step, the more likely to be offset but the smaller the vortex impact area. When the distance between the air outlet and the upper working surface is larger, the large eddy current is more likely to appear in front of the work on the step. The value of L1 is preferably 5-10m; 5) The shorter the step, the greater the effective range of the jet. When the length of the step exceeds a certain length, the impact on its flow field is small. The length of the upper step L2 is preferably 5 ~ 10m, but it should be less than L1; 6) In order to avoid space constraints and ensure the full development of the jet, the height L3 of the upper step should be less than the height of the air duct arrangement, should be 4-5m.