[Triccio]

I have to model a stationary spray-jet impinging on a flat and vertical surface with an angle of impingement at 90 in order to evaluate the shear stress generated over the flat surface in function of inlet pressures and standoff distances .

The scope of this model is to simulate the cleaning of flat collectors in CSP plants.

I have defined a volume of control characterized by a quite dense mesh ,manually refined, creating the following boundaries: Inlet, Atm and Wall.

Inlet : where I set the inlet pressure
Atm : volume of control with atm pressure
Wall : a vertical flat surface

I need to validate my result with a break up model.

Does CFX have any model which can suit this case?

Thanks in advance

[ghorrocks]

I am no expert on spray breakup so cannot say.

How about you look in the documentation and see what models are available and how they work. You are the best person to determine if the available models are suitable for your application.

[Triccio]

Originally Posted by ghorrocks

I am no expert on spray breakup so cannot say.

How about you look in the documentation and see what models are available and how they work. You are the best person to determine if the available models are suitable for your application.

Ok thanks for your reply, do you know any person to suggest I can contact in this forum to have more info about break up models ?

[ghorrocks]

You have already put a post up, hopefully somebody sees it and will post.

Also: while I am not expert on spray breakup it does not mean I know nothing about it

The spray breakup models in CFX are designed for spray formation from injectors - specifically fuel injection nozzles. As this does not involve impact with the wall they are not appropriate. So the spray models which involve particles hitting a wall are the particle-wall interaction models and quasi static wall film model. The particle wall-interation model looks like it is focussed on droplets hitting walls, not jets; and the quasi static film model is based on a wall films found in internal combustion engines which does not have much of a correlation to the jet impacting a plate you are looking at.

So my assessment is that there is no model in CFX by default which will give useful results for spray creation from a jet hitting a plate.

I would look in the literature for a benchmark result.

[Triccio]

Originally Posted by ghorrocks

You have already put a post up, hopefully somebody sees it and will post.

Also: while I am not expert on spray breakup it does not mean I know nothing about it

The spray breakup models in CFX are designed for spray formation from injectors - specifically fuel injection nozzles. As this does not involve impact with the wall they are not appropriate. So the spray models which involve particles hitting a wall are the particle-wall interaction models and quasi static wall film model. The particle wall-interation model looks like it is focussed on droplets hitting walls, not jets; and the quasi static film model is based on a wall films found in internal combustion engines which does not have much of a correlation to the jet impacting a plate you are looking at.

So my assessment is that there is no model in CFX by default which will give useful results for spray creation from a jet hitting a plate.

I would look in the literature for a benchmark result.

I didn't say and ever thought that

OK that is interesting and helpful. I will have a look at the the particle-wall interaction models first which look promising for my case.

Thanks for the advices

[Triccio]

Have you guys any tutorial to suggest for modelling droplet with CFX ?

[ghorrocks]

If the tutorials provided with CFX do not cover what you want then contact ANSYS support as they have lots of more specialised examples.