Investigation On Adhesion Characteristic Of Wheel/Rail Under Third Medium Conditions

The adhesion characteristic of the wheel/rail interface is the most important influencing factors in railway transportation. Acceleration and deceleration of the trains are completed using the adhesion force between wheel and rail. Therefore, the adhesion characteristic of the wheel/rail interface has significant influence on the safety, comfortableness and economy of the trains.In this paper, a numerical model of steady partial EHL lubrication was established using Patir and Cheng average flow model based on two dimensional rolling contact theory and partial EHL theory considering roughness of two contact surfaces. The numerical model was solved using multi-grid method. The effects of rolling speed, contact load, surface roughness, and diameter of wheel and viscosity of third medium on adhesion coefficient were explored in detail. In addition, the effects of rolling speed and contact load on adhesion coefficient of wheel/rail under the water lubrication or oil contamination conditions were studied using JD-1wheel/rail simulation facility. There was a comparative analysis between experimental results and numerical results. Main conclusions are draw as follows:1. The numerical results indicate that the adhesion coefficient of wheel/rail under the oil contamination condition is less than that under the water lubrication condition. The adhesion coefficient of wheel/rail increases with an increase of surface roughness and wheel diameter. However, the adhesion coefficient decreases with an increase of rolling speed, contact load and viscosity of third medium. The rolling speed and surface roughness are most important influencing factors on the adhesion characteristic of wheel/rail. The viscosity can change the film thickness of the third medium and has significant effect on adhesion coefficient.2. The experimental results indicate that the adhesion coefficient of wheel/rail decreases with an increase of rolling speed and contact load under the water lubrication or oil contamination conditions.3. The analysis of numerical and experimental results shows that there is same changing trend between the curves of numerical and experimental results. However, there is some difference between numerical and experimental results because some influencing factors were carried out simplified treatment on the numerical simulation process. The error between numerical and experimental results is less than10%.