Investigation of newtonian liquid jets impacting on a moving smooth solid surface

Injection of a high speed liquid jet on a fast moving smooth surface and its splash are important in many practical applications such as railroad industry in which a friction modifying liquid may be applied to the rail or to the wheel in the form of a liquid jet. An experimental study was conducted to measure the splash of six different Newtonian liquids with widely varying shear viscosities to isolate the effect of viscosity on splash behavior after impaction. High speed video imaging was employed to scrutinize the interaction between the impacting jet and the moving surface. For Newtonian liquids, decreasing the Reynolds number reduced the incidence of splash and consequently enhanced the transfer efficiency. At the elevated Weber numbers of the testing, the Weber number had a much smaller impact on splash than did the Reynolds number. The ratio of the jet velocity to surface velocity has only a small effect on the splash but it was observed that the both normal (jet velocity) and tangential (surface speed) speeds play roles in splash-deposition dynamics. Increase in viscosity causes the lamella thickness to increase and also helps in reducing the amount of splash and as a result increase transfer efficiency.