Fluids

Fluids

Rebounding of droplet from the wall below boiling temperature

    • emonome
      Subscriber

      Hello Guys,

      I am doing a simulation of droplet impingement on a glass wall. As you can see in the wall interaction criteria from the ANSYS theory guide, droplets went through the stick, spread, and splash depending on the impact energy below boiling temperature. Even though My impact energy is very low, I still can see some droplets rebounding from the wall. Is this effect comes from the wet wall or interaction with exiting wall film on the wall? For your information, I am using a Discrete phase model with wall boundary conditions (wall film). Does fluent consider the wet wall effect? Unfortunately, there is no information regarding this. Please help me.

    • Rob
      Ansys Employee
      Are you using the Lagrangian Wall Film (film condition in the DPM part or Eulerian Wall Film?
    • emonome
      Subscriber
      Just lagrangian wall film only for DPM part.
    • Rob
      Ansys Employee
      Check the text under https://ansyshelp.ansys.com/account/Secured?returnurl=/Views/Secured/corp/v211/en/flu_th/flu_th_sect_wall_film_impact.html Eqn 16-232 otherwise check the particle velocity etc to see if you're close to splashing.
    • emonome
      Subscriber
      Thank you for your answer. Unfortunately, there is no chance of splashing. as the particle velocity is very low. I was wondering if it is beacuse of the vortex created near the wall. Though some of the particle stick on the wall, the later one just move along with the vortex. Hence it felt like rebounding. Also in Stanton paper (Modeling Fuel Film Formation and Wall Interaction in Diesel Engines), He mentioned about rebound regime which occurs when the impinging drop bounces off the film when the impact energy is low. The air layer trapped between the drop and the liquid film causes low energy loss resulting in bouncing. The transition criteria for the rebounding regime is 5 < We < 10. I was wondering if happens in fluent too.

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