Impact Analysis Of Shaft & Cross Aile On High-Speed Railway Tunnel Exit Micro-Pressure Wave

Aerodynamics problems, which will be induced when a train is entering into tunnel, follow the development of high-speed railway. And the problems have been viewed as a hot topic and advanced research by scholars in various countries. The aeordynamics problems will be highlighted as higher train speed. Micro-pressure wave problem is one of the importances of aerodynamics problem; the study lays stress on formation mechanism and alleviating measures. China, which is a mountainous country, has entered into a new great-leap-forward development age leading to many long and large tunnels be bound to constructed. Therefore, it is more urgent current demand that lucubration of tunnel aerodynamic effect's mechanism and corresponding alleviation measure, which wound be make a significant impact on high-speed railway advancing constantly.In this thesis, model testing and digital simulation were used to carry on the research, for studying the laws of influences of shaft and cross aile on tunnel pressure change and exit micro-pressure wave.These were made definite that function mechanism and alleviating effect of shaft and cross aile alleviating aerodynamic effect by model testingMany working conditions with different amounts of shafts or cross ailes and intercombination were simulated by CFD software FLUENT. By relative analysis, conclusions are concluded as follows:1. Both peak reduction efficiency and secondary peak effect of shaft could be more evident than that of cross aile.2. Peak reduction rate had no reference to train speed, which was a function of sectional area.3. Secondary peak was a function of sectional area and train speed.4. Both peak reduction efficiency of series connection of shafts or cross ailes could be more evident than that of parallel connection with respect to compound mode.For the above-mentioned conclution, a total reduction formula of shafts and aile crosses which assembled in series was proposed. Meanwhile, an iterative computating formula about shaft or cross aile was derivated, principle of optimal combination and procedure was established by proposed critical condition.