Fluid Field Analysis Of Hydraulic Damper In Railway Vehicle

Hydraulic damper of Locomotive and Rolling Stock is a key component of running components which can absorb and ease road irregularities caused by vibration and shock. Its performance has a direct impact of the train's stability, comfort, the service life of vehicle parts and traffic safety.With the prompt development and operation of the high-speed train, the development of the structure and performance of hydraulic dampers satisfied completely for the utilization in high-speed trains is imminently required. The domestic application research of hydraulic dampers is insufficient, the testing equipments are outdated and products development cycle is too long, although there is huge gap between the performance of hydraulic dampers in china and that of the other countries. The new speeded-up locomotives all use the shock absorbers from developed countries. However, the cost of the imported products and its maintenance is high, if the domestic factories can produce the hydraulic dampers that meet the requirement of high-speed locomotives, we can greatly reduce the cost of the rolling stock equipment.In order to exploit advanced designs and performance prediction methods about shock absorbers, by means of the computer simulation technology of computational fluid dynamics, this thesis has accomplished flow field analysis and three-dimensional simulation of the varied damping valves and the whole internal chamber.In this thesis, the research tasks include:1. According to damping theory of squeezing film, establish flow balance equation and mechanical equilibrium equation and figure out the piston velocity and the damping valve height by MATLAB software.2. according to the specific structure and geometric parameters of SS₉ hydraulic dampers, , establish the geometric model of damping valves and the whole flow chamber of shock absorber in applying Pro/E software, partition geometric model grid and set up the moving mesh properties and the dynamic boundary conditions by ANSYS ICEM.3. In application of flow analysis software CFX, complete three-dimensional simulation of flow field and characteristics analysis of the damping valves and the overall chamber model. 4. Extract flow field data to plot pressure distribution curve of the working part of the throttle valves, achieve the velocity-pressure curve and the indicator diagram, analyze the impact of damping hole diameter, damping hole length, spring pre-compression and stiffness on the damping force.The computational flow analysis can understand the mechanism of its work in further, it also has great benefit for the hydraulic damper design and performance prediction. The results also coincide with the test standard, indicating that CFD simulation is a powerful tool to optimum design.