The Calculation Of Intake Flow And Negative Pressure For Diesel Engine In High Altitude Tunnel With Different Locomotive Speed

With the rapid growth of our national economy and the country's long term attention to the transportation industry,China's railway transportation,especially high speed railways,has created one miracle after another and has made remarkable achievements.However,in the high altitude areas such as the Qinghai-Tibet Plateau with harsh environment and sparsely populated,also the cost of electrification is high.Therefore,diesel powered locomotives still carry the major transportation tasks.The intake flow is a key parameter and prerequisite for diesel engine work.To determine whether the diesel engine can operate within a reasonable range in a long tunnel with high altitude,it is necessary to analyze and calculate the intake air quantity and intake negative pressure.In the design stage,the analysis of the external flow field of the train at high altitude tunnels is performed through the aerodynamic simulation method,In particular,the analysis of the intake pressure at the suction grid,combined with the analysis of the diesel engine's working performance,forms the calculation method for the intake air volume of the diesel engine when the locomotive crosses the tunnel,and proposes a speed scheme for the locomotive carrying the researched model when passing the tunnel.For the follow-up real vehicle test,provide an effective reference.This paper adopts the Fluent Sliding Mesh Method to simulate the diesel inlet pressure when the locomotive passes the tunnel at a speed of 40km/h,50km/h and 60km/h.The third chapter of this paper verifies the veracity of the simulation,and then combines the turbocharged diesel engine principle,starting from the diesel engine performance,puts forward a diesel engine air intake algorithm when a certain high-type locomotive equipped with a 12-cylinder V diesel engine passes through a tunnel.Calculate the permissible intake negative pressure value of-162 Pa for ensuring the normal operation of the diesel engine in the tunnel,and accordingly propose a preliminary speed plan for the locomotive to cross the tunnel.However,due to the actual altitude conditions in the high altitude area of 4200 m,the design power and design row are satisfied.The locomotive can be operated in the tunnel to 1758 m,and the exhaust temperature of the turbine can be stabilized as near as possible at 650°C by reducing the diesel engine power and load and combining certain oxygen supply measures.