Free surface lubrication of rotating cylinders by impacting Newtonian liquid jet

Abstract

Free surface lubrication of rotating cylinders by Newtonian liquid jets was investigated at different impingement positions, jet‐ and circumferential velocities. The interaction between impinging round laminar jet and rotating surface was characterised by high‐speed imaging. Compared to flat surface impingement, the liquid deposition mechanism is more complex and often accompanied by phenomena such as splashing, jet deflection and formation of radial surface stripes. Liquid splashing initially develops in direct deposition regime due to hydraulic jump‐induced droplet shedding, transitioning to lamella instability splash at higher Reynolds numbers. The critical Reynolds number for splash onset is of same order of magnitude as for flat surface impingement and fairly constant at low relative jet impingement angles, but increases exponentially when angle approaches 90°. Liquid film width and thickness were both determined proportional to the square root of the jet/surface velocity ratio, with respective power law models in good agreement with measured values.

A Liquid Jet Impinging onto Rotating Convex Superhydrophobic and Hydrophilic Surfaces: Reflection or Deflection?

“…Kibar (2017) has experimentally and numerically examined the impingement of a liquid jet on hydrophobic and superhydrophobic convex surfaces in a stationary situation. In this study, the reflection or deflection (teapot effect) of the liquid jet impinging the convex surface is dominated by the capillary adhesion interaction between the superhydrophobic and hydrophobic surfaces Bizjan et al (2021). have experimentally investigated the flow behavior of a liquid jet impinging on a rotating cylindrical surface at different jet velocities, cylinder rotation speeds, and impingement positions.…”