DPM Collection on Eulerian Wall Film (Weird Interaction)
 

Dear Experts,

In ANSYS Fluent,

I can have Discrete particle impinge on wall and form film or splash or rebound depending on impact Energy (E) and temperature of wall film T_w.

However, I just specify solve momentum, dpm collection and edge seperation (We_critical = 5, Angle Crit = 90).

My question is why is the particle reflect and what formulation dictates the reflection angle. It been navigating and could not understand the interaction well.

I knew that DPM collection means that the dpm mass source = wall film mass source when interact. And its momentum is bla bla eqn. Meanwhile, the wall film is actually tracked using particle method as well which is based on total number of particle in the cells (Therefore, Continuum air = Eulerian method Navier stokes, Discrete phase trajectory balance = Lagrangian formula of force balance , Eulerian wall film = transient particle tracking method)

From my understanding if splashing is on and if E = 57.7 the additional droplets will form and the mass will be taken from experimental data Mundo et al or its particle sizes. However my splashing is not on. Which seems ok when the droplet size does not change when hitting wall. However it reflected at a certain angle.

I know that when droplet has high momentum and hit it has tendency to reflect. However, I cant find any explanation in Fluent guide. I just knew that Eulerian wall film surpress the DPM BC (Trapped, reflect or wall jet).

If it reflects the only things I could imagine is it is in spread regime E > 16 and is automatically applied with wall jet theory.

Can someone help me with it

The attachment is below, replicate of Arienti Experiments.

Thanks

Kind Regards,
JL

Hi JL
could you find the answer for your problem?
I am facing something similar. I want to quantify the target efficiency of particles to an area.
I started using DPM and trap as the boundary condition. However, I couldn't report the location of the trapped particles.
So I was advised to use Wall film and to report the absorbed particles. However, I am confused about which conditions should I include in the wall film model since I don't want my particles to lose their diameter and form.

do you have any clue or advise?