Numerical Simulation And Optimization Of Air Distribution Of Air Conditioning In A Railway Station

The flow resistance of the tunnel and the boosting capacity of jet fan in the tunnel are the foundation to calculate the tunnel ventilation, they are the first ascertained parameters. The Jinping tunnel is a double-line form hole, there are transverse passways and emergency parking place, because its structure is special, The flow resistance of tunnel and the boosting capacity of jet fan is difficult to ascertain, there are not datum to be used for reference at present. This dissertation relies on one project. It is "Simulation research on three-dimensional wind pressure and velocity in the tunnel ", CFD method is adopted to carry on numerical simulation research on the pressure and velocity in the tunnel. The flow resistance of the tunnel and the boosting capacity of jet fan are calculated, the analyses are done to the different factors that influence the flow resistance and boosting capacity, the results of study will be applied to actual project directly.The Jinping B tunnel is the main research object, this dissertation builds different computational models due to the actual dimension of the tunnel and jet fan, and the position to install the jet fan. The STAR-CD software is used to realize the three-dimensional simulations of the pressure field and velocity field. Navier-Stokes equation is the governing equation of the computation and k-ε turbulent model is employed. The finite volume method is used to discretize the computed area. When dealing with the boundary condition in the area near the wall, the wall function is adopted. In addition, the upwind differencing scheme is used in the computation. And the SIMPLE algorithm is adopted to couple the speed and pressure.This dissertation has calculated the friction resistance coefficient and the local resistance coefficient of the tunnel at first, and the simulation result is compared with the result of the test, verifying the exactness calculated in simulation. In addition, the impacts on the local resistance coefficient of the tunnel are analyzed that roughness of the tunnel, the way that tunnel connect transverse passways and opening the transverse passways;At the same time this dissertation calculate the boosting capacity of the jet fan when jet fan is installedin emergency parking place of the tunnel.Many impacts on the boosting capacity of jet fan are analyzed , including theroughness of the tunnel side , transverse passways connected the angle with mainhole , different jet fan type , installation site , installation interval, the numberof silencer and the number of installation jet fan. These analyses offer the basisin order to optimize the arrangement of the jet fan and type selection. And therule of the longitudinal airflow, velocity and pressure distribution is achieved, thejet fan influence to the tunnel flow field is analyzed.