Investigation Of Heat And Humidity Condition In Railway Tunnel

The climate condition in railway tunnels would be deteriorated as trains passing through. Especially in long tunnels, uncommon climate conditions are expected due to the extra length. Furthermore, the scheduled heavy traffic for passenger and freight trains as well as the high speed will lead to a climate in long tunnels deviating considerably from existing common tunnels. The unapt in tunnel climate will not only influence the reliability of equipments but also will be harmful to safety of the trains.This dissertation relies on the project of "Research on hazard prevention, rescue, safe evacuation and ventilation in Super-Long Tunnels". Numerical simulation research on the heat condition and humidity is presented. One-dimensional incompressible unsteady flow theory has been used to simulating the air flow in tunnels. The unsteady heat transfer simulation is based on the simulating method of temperature and humidity in a longitudinally ventilated long tunnel raised by Iguchi (Japan). Finite volume method are used when generate discrete computed domain and boundary. Conditions of the rocks around, air in the tunnel, trains conditions are considered.Aerodynamic model, heat transfer model as well as computation method has been built for railway tunnels; a simulation tool program has been developed; simulation and analysis of heat conduction both in ground surrounding single tunnel and twin tunnel are presented and the influence of different outside climate condition has been compared. Temperature and humidity distribution during the earlier period has been obtained. The influence of different rock temperature, train alternation and different meeting place has been studied, the reasons has been analyzed too.According to the consequence of this dissertation, some parameters and the influence of them has been given, rock temperature and the climate outside are the most important parameters; both high rock temperature and high outside air temperature can lead to a unacceptable temperature in railway tunnels. Both temperature's value and temperature distribution along tunnel will be changed if one of the parameters is changed.At last, the models and method established in this dissertation can be used to predict the temperature and humidity condition of real projects by improving some construction parameters and changing initial and boundary conditions.