基于铁氧化物以及大气污染引起的轮轨黏着问题研究

Wheel-rail adhesion is essential for keeping a safe, punctual operation and low maintenance cost. Due to its open nature, wheel-rail adhesion is influenced by various contaminants and environmental conditions. Therefore, the adhesion mechanism is very complicated. The research carried out in China and overseas hasn't fully understood the phenomena and influential factors. Most of the research focuses on investigating traditional contaminants. Based on the applicant’s recent work, the iron oxides generated on the wheel and rail surfaces significantly change the friction coefficient. Environmental conditions, such as temperature and humidity, can affect the type of the iron oxides and the oxidation rate, which leads to adhesion problems. Moreover, the air pollution in China further influences the generation of the iron oxides, causing new problems in the wheel-rail adhesion. Therefore, the iron oxides and air pollution are important factors causing adhesion problems between the wheel and rail. As a result, this project investigates the generating process of the iron oxides based on various environmental conditions including the air pollution. This information can be related to the friction coefficient of different iron oxides. Thus the adhesion model with regard to the iron oxides and air pollution under typical conditions can be developed. On the other hand, based on wheel-rail prediction system and improving wheel slide protection system, measures which mitigates the wheel-rail adhesion problems can be achieved through experiments. The research project could provide theoretical background and technical support for solving the problems caused by the wheel-rail adhesion.

轮轨间的黏着力，对列车安全、准时运行，降低维护费用有着重要意义。由于轮轨接触具有开放性，轮轨黏着直接受污染物、环境因素的影响，机理十分复杂。国内外对其机理、影响因素的研究尚不全面，大多数集中在以传统污染物为主要研究对象的方向。申请人近期研究发现，轮轨表面的铁氧化层会极大地改变摩擦系数；环境因素，如温度和湿度，又会影响铁氧化层产生的种类和速率，产生黏着问题。而我国目前的大气污染，改变了铁氧化物的生成规律，从而产生新的轮轨黏着问题。因此，申请人认为铁氧化物以及大气污染是导致轮轨黏着问题的重要因素。鉴于此，本项目研究在包含大气污染的各种环境条件下，轮轨表面铁氧化物的生成机制，并与其摩擦系数相关联，构建典型工况下基于铁氧化物和大气污染的轮轨黏着理论模型。同时，立足于轮轨预测系统和改进车轮防滑系统，通过台架试验，提出减轻轮轨黏着问题的方案。通过本项目的研究，为解决轮轨黏着问题提供理论基础和技术支持。

轮轨接触是一个开放系统，受污染物、环境因素的影响较大。而轮轨间的黏着力对列车安全、准时运行以及降低维护费用十分关键。本项目通过还原现场环境，利用环境箱在轮轨材料表面生成不同的氧化膜，通过对比揭示了轮轨材料表面铁氧化物的产生机理，并建立了关键环境影响因素和铁氧化物之间的关系；利用盘销实验对不同环境条件下的轮轨摩擦系数进行了测量，建立了基于温度和湿度的摩擦系数图谱，揭示了氧化膜中主要成分对摩擦系数的影响规律；利用双盘试验机对不同滑差下的轮轨黏着系数进行了研究，揭示了滑差率在干态以及水润滑下对粘着系数的影响机制，同时对轮轨磨损进行了测量，研究了氧化膜、粗糙度等因素对轮轨磨损率的影响规律，提出了利用控制表面粗糙度进行增粘的方案，同时也对利用金属增材制造修复磨损严重的轮轨型面进行了初步探索。