高原区内燃牵引2～4km单线隧道自然通风可行性分析

Feasibility Analysis of Natural Ventilation of an Internal-Combustion Tract Single-Line Tunnel between 2-4 km in the Plateau Region

基于关角隧道、羊八井隧道内燃牵引机车有害气体浓度冬季监测结果,以及拉日线隧址区现场风速观测,提出了拉日线隧道外自然风速的建议值。通过对隧道热位差产生的隧道内自然风速的计算,以及隧道内风速和污染物浓度一维非恒定流数值模拟,确定了隧道内自然风速的合理取值,计算了活塞风风速及活塞风长度;分析了拉日线3 000～4 070 m长度隧道全年内可实现自然通风的时段。研究表明,长度3 000 m以下的隧道,运营期间可实现自然通风;长度3 000～4 070 m的隧道采用自然通风,可在远期运行图周期内使有害气体达标。

Based on monitoring results indicating harmful gas concentrations in the Guanjiao and Yangbajin tunnels along the Qinghai-Tibet railway in winter and the observed wind speed in the tunnel zone of the Lbasa- ltikaze railway, the recommended natural air speed outside of a tunnel is presented. The reasonable natural air speed value inside of a tunnel was determined and the speed and length of piston air were calculated based on calculations of natural wind speeds deternfined by thermal potential difference in the tunnel and a one-dimensional unsteady flow simulation for air speed and pollutant concentration in the tunnel. Furthermore, the time period when natural ventilation is available was analyzed for tunnels measuring 3000-4070 m in length. Results indicate that natural ventilation mode may be used during the operation of tunnels less than 3000m. Regarding tunnels measuring 3000-4070 m, natural ventilation may achieve health standards with long-term planning.