High Speed Liquid Jet and Droplet Impaction on a Moving Surface

Kelsan技术公司采用喷嘴将一种专有的液体摩擦改进剂（FM）薄膜分布在传统铁路轨道的顶部表面。除了减少轨道上的摩擦外，Kelsan的专利FM液体KELTRACK®还减少了火车燃油消耗，以及轨道和车轮法兰的磨损。目前的调频应用方式是通过喷嘴雾化调频液体，在侧风存在的情况下，调频液体不均匀地分布到轨道上，导致调频液体被带回喷嘴，导致喷嘴结垢。为了改善与侧风中喷雾偏转有关的问题，我们将研究高速液体射流的调频应用。为了研究地表移动速度与火车速度相当（约200公里/小时）时的LFM撞击，我们将把LFM射流喷射到旋转磁盘设备上。我们将测量喷嘴背压和直径、轨道速度和粗糙度、LFM成分以及LFM和轨道温度对射流撞击的影响。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作用。我们将建造一个真空室，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撞击的影响。为了研究单个液滴在高速运动表面上的撞击，我们将构建一个液滴向运动带对流的风洞装置。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射流所处的环境，我们将测量一列移动的火车下面不同位置的当地空气速度，并将这些结果与火车附近测量的风速进行比较。拟议的研究将改进轨道上使用的FM应用方法，增强KELTRACK®在减少轨道摩擦，节省燃料和轨道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.