High Speed Liquid Jet and Droplet Impaction on a Moving Surface

凯尔桑技术公司使用喷嘴将一种专有液体摩擦改进剂(FM)的薄膜分散到传统铁轨的顶部轨道表面。除了减少轨道上的摩擦，凯尔桑的专利FM液体KELTRACK®还降低了火车的燃油消耗以及钢轨和车轮的法兰磨损。目前的FM应用模式是通过喷嘴喷洒FM液体雾化，在有侧风的情况下，FM不均匀地分布在轨道上，导致FM液体被带回喷嘴，导致喷嘴结垢。为了改善侧风中与喷雾偏转相关的问题，我们将研究利用高速液体射流来应用调频技术。为了研究表面以与火车速度相当的速度运动的线性调频撞击(&gt；200公里/小时)，我们将线性调频喷嘴弹射到旋转的圆盘设备上。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、线性调频和导轨温度对射流冲击的影响。由于液体射流撞击表面的空气边界层会影响飞溅，因此我们还将研究周围空气压力对液体射流撞击的影响。我们将建造一个真空室，在其中液体射流撞击运动的皮带。通过改变装置内的环境空气压力水平，我们将测量空气压力对射流撞击的影响。为了研究单个液滴对高速运动表面的撞击，我们将构建一个液滴对流到运动带上的风洞装置。测试将使用不同的液滴溶液、表面粗糙度、风洞和表面速度进行。最后，为了了解FM喷流所处的环境，我们将测量移动列车下方不同位置的局部空气速度，并将这些结果与在距离列车一段距离时测量的风速进行比较。这项拟议的研究将改进铁轨上使用的FM应用方法，增强KELTRACK®在降低钢轨摩擦、节省燃料和维护轨道设备方面的有益效果。

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.