Application of Friction Modifier to Railroad Tracks

该提案涉及UBC和LB Foster铁路技术公司之间的两个不同但相关的合作项目。这两个项目都是将摩擦改进剂应用于铁路轨道，以优化车轮与轨道之间的摩擦系数。一个最佳的摩擦系数是一个足够高，以允许爬坡和安全制动，但低于金属对金属的系数。与未涂覆的轨道相比，涂有摩擦改进剂的轨道摩擦系数降低，轨道磨损率和噪音产生率降低，燃油经济性提高。目前用于将摩擦改进剂应用于铁路轨道的一个过程是将一池粘性摩擦改进剂液体渗到轨道上。当火车车轮经过水池时，液体覆盖在车轮上，车轮上的液体涂层被火车的运动带到下游，覆盖在更远的下游轨道上。这个过程的机制是相当复杂的，因为它们涉及池的自由表面和移动的轮子之间的相互作用。我们已经开发了一个很好的模型，当车轮非常宽时（即，流动是二维的），液体是牛顿的，我们现在计划扩展理论和实验，以理解非牛顿液体的三维问题。正在考虑的第二个过程是使用静电粉末喷雾器将摩擦改进剂粉末从移动的火车转移到轨道上。在这种应用中，要允许静电粉末喷涂，至少必须克服两个主要障碍：静电喷雾将暴露在侧风中，而油漆喷涂通常是在喷涂室中完成的；摩擦改性剂粉末要么是半导体，要么是导体，这比典型的（绝缘）油漆粉末喷涂更具挑战性。这里的目标是使静电粉末喷涂在轨道涂层中可行。

This proposal involves two different, although related, collaborative projects between UBC and LB Foster Railroad Technologies Corporation. Both projects concern the application of friction modifier onto railroad tracks, to optimize the coefficient of friction between the wheel and the track. An optimal coefficient of friction is one that is sufficiently high to permit hill climbing and safe braking, but is lower than the metal-to -metal coefficient. The reduced coefficient of friction of a railroad track with friction modifier results in lower rates of track wear and noise production, and improved fuel economy, relative to an uncoated track.One process that is currently used to apply friction modifier to railroad tracks involves oozing a pool of viscous friction modifier liquid onto the tracks. As a train wheel passes over the pool, the liquid coats the wheel, and the liquid coating on the wheel is carried downstream by the motion of the train, coating the track farther downstream. The mechanics of this process are quite complex, as they involve the interplay between the free surface of the pool and the moving wheel. We have developed a good model for the process when the wheel is extremely wide (i.e., the flow is two-dimensional) and the liquid is Newtonian, and we now plan to expand both the theory and experiments to understand the three-dimensional problem with a non-Newtonian liquid.A second process under consideration is the use of an electrostatic powder sprayer to transfer friction modifier powder to the track from a moving train. There are at least two major hurdles that must be overcome to permit electrostatic powder spraying in this application: the electrostatic spray would be exposed to crosswinds whereas paint spraying is normally done in a spray booth, and friction modifier powder is either a semiconductor or a conductor, which is much more challenging to spray than the typical (insulating) paint powders. The goal here is to make electrostatic powder spraying practicable for track coating.