High Speed Liquid Jet and Droplet Impaction on a Moving Surface

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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.