Continuous dip-coating flow in the presence of a liquid-liquid interface

ORAL

Abstract

Dip-coating is a widely utilized industrial process for applying protective coatings over substrates. Landau and Levich's theoretical analysis highlighted the key viscous-capillary interactions. The process becomes complex with liquid-liquid interfaces, as seen in multilayered coatings. This study explores the continuous dip-coating of a wire in a two-immiscible liquid system, focusing on the fluid dynamics at the liquid-liquid interface and the resulting film coating. Both experimental and numerical analysis reveals multiple flow regimes: visco-capillary, visco-inertial, boundary layer-dominated, and visco-gravitational. Our findings extend the Landau-Levich law beyond the classical capillary number values and show a distinct visco-inertial regime with a sharp, delayed transition. At high inertia, boundary layer effects reduce film thickness, while a visco-gravitational regime emerges when inertia is minimal and diminishing capillary suction effectiveness.

*Jishnu Goswami would like to acknowledge JNCASR for the fellowship during his M.S. (Engg) degree.

Publication: Goswami, J., Zoueshtiagh, F., Sreenivas, K.R. (2023). Investigation of Dip Coating Process of a Wire Through Experimental and Numerical Simulations, Fluid Mechanics and Fluid Power Conference, India (Accepted for publication, to be published in Lecture Notes in Mechanical Engineering series-Springer

Presenters

  • Sreenivas Sreenivas

    • Jawaharlal Nehru Centre for Advanced Scientific Research
    • Engineering Mechanics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bengaluru 560064, India

Authors

  • Jishnu Goswami

    • Jawaharlal Nehru Centre for Advanced Scientific Research
  • Farzam Zoueshtiagh

    • Universite of Lille
  • Sreenivas Sreenivas

    • Jawaharlal Nehru Centre for Advanced Scientific Research
    • Engineering Mechanics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur PO, Bengaluru 560064, India