Research On The Effect Of Thermal-Fluid-Structure Coupling On The Performance Of Braking Of High-Speed Railway Vehicle

As the speed of passanger trains accelerates constantly, many shortcomings are exposed in designing of its braking process. For example, the heat energy genaerated by friction of brake parts suffers a great increase, the materials of frictional parts bear transformations in microstructure under high temperature and the structure of braking disc come to influence the overall resistance of the train substantially. Two kinds of effects occur during braking, namely the heating of disc by the thermal energy from frictional pairs and heat dissipation of disc immersed in high speed flow. So it is necessary to address the problem in to aspects, on one hand is the thermal-structure coulping analysis of heating process and on the other hand is the property of braking disc in thermal dissipation and aerial resistance. Based on the outline above the content in this paper is following:1) An simulation model for thermal-structure coulping analysis is constructed.The distributions and developments of transient temperature and stress on the surface and cutting sections of the disc are obtained under the assumption of a constant and uniform convective heat transfer coefficient.2) A computational fluid dynamics analysis is conducted aimed at the aerial resistance property of the disc. The flow distribution around the disc is obtained with consideration of both the rotation and linear motion of the disc. The mechanism of the generation of aerial resistance is analysed based on the velocity distribution above and the value of the resistance is calculated.3)A similarity model for simulation is constructed to calculate the convective heat transfer coefficient in accordance with the similarity theory in fluid mechanics.The distribution and variation of the coefficient are obtained by taking advantages of the dynamic mesh technique, UDF programming and the results obtained in thermal-structure analysis. The coefficient data are extracted from Fluent and loaded in the thermal-structure model, thus the distribution and variation of temperature andstress field are obtained,by submitting the reloaded model into computation, under the influence of all the three physical field of thermal, flow, and structure.