High Speed Liquid Jet and Droplet Impaction on a Moving Surface

Kelsan Technologies Corporation采用喷嘴将专有液体摩擦改性剂（FM）的薄膜分布到常规铁路轨道的顶部轨道表面上。除了减少铁轨上的摩擦外，Kelsan的专利FM液体KELTRACK®还减少了火车的燃料消耗，以及铁轨和轮缘的磨损。FM施加的当前模式涉及通过喷嘴施加的FM液体雾化，在存在侧风的情况下将FM不均匀地分布到铁轨轨道，导致FM液体被带回到喷嘴上，从而导致喷嘴结垢。为了改善喷雾偏转的问题，我们将通过高速液体射流来研究FM的应用。为了研究LFM与以与火车速度（>200 km/h）相当的速度移动的表面的碰撞，我们将LFM射流喷射到旋转盘装置上。我们将测量喷嘴背压和直径，轨道速度和粗糙度，线性调频成分，线性调频和轨道温度对射流冲击的影响。由于液体射流冲击表面上的空气边界层会影响飞溅，我们还将研究周围空气压力对液体射流冲击的作用。我们将建造一个真空室，在其中液体射流冲击移动的带。通过改变设备内的环境空气压力水平，我们将测量空气压力对射流冲击的影响。为了研究单个液滴在高速运动表面上的碰撞，我们将构建一个风洞装置，在该装置中，液滴被对流朝向运动带。将使用不同的液滴溶液、表面粗糙度、风洞和表面速度进行测试。最后，为了了解FM射流所处的环境，我们将测量移动列车下方不同位置的局部空气速度，并将这些结果与远离列车的风速进行比较。拟议的研究将改进FM在铁路轨道上的应用方法，增强KELTRACK ®在减少轨道摩擦、节省燃料和铁路设备维护方面的有益效果。

Spray nozzles are employed by Kelsan Technologies Corporation to distribute a thin film of a proprietary liquid friction modifier (FM) onto the top rail surface of conventional railroad tracks. In addition to reducing friction on rail tracks, Kelsan's patent FM liquid, KELTRACK®, has reduced train fuel consumption, and rail and wheel flange wear. The current mode of FM application, involving FM liquid atomization through spray nozzle application, distributes FM to rail tracks unevenly in the presence of a cross-wind, causing FM liquid to be carried back onto the spray nozzle, resulting in nozzle fouling. To ameliorate the problems associated with spray deflection in a crosswind, we will study the application of FM by means of a high speed liquid jet. To study LFM impingement with a surface moving at velocities comparable to train speeds (>200 km/h) we will eject an LFM jet onto a spinning disk device. We will measure the effects of nozzle back pressure and diameter, rail velocity and roughness, LFM composition, and LFM and rail temperature on jet impingement. Because the air boundary layer on the surface upon which a liquid jet impinges affects splash, we will also study the role of surrounding air pressure on liquid jet impingement. We will construct a vacuum chamber in which a liquid jet impacts a moving belt. By altering ambient air pressure levels within the device, we will measure the effect of air pressure on jet impingement. To study single droplet impaction on a high speed moving surface, we will construct a wind tunnel device in which a liquid droplet is convected towards a moving belt. Tests will be run using different liquid drop solutions, surface roughnesses, and wind tunnel and surface velocities. Finally, to understand the environment to which the FM jet is exposed, we will measure the local air velocity at various locations underneath a moving train, comparing these results with the wind velocities measured at a distance away from the train. The proposed research will refine FM application methods used on rail tracks, enhancing KELTRACK's® beneficial effect on top of rail friction reduction, fuel saving and rail equipment upkeep.