Temperature dependent Stick-to-Wall
 

Hello,

We are simulating a turbine guide vane with ash particles present in the flow. We would like to know if there is a way to put a condition on the Stick-to-Wall Model, so that it will be used only if the temperature of the particle exceeds a certain value? A particle with lower temperature is supposed to bounce of the surface.

How do we write the code (if there is a way), specifying the temperature and wall behaviour? We are completely new to Fortran and CEL so any guidance would be greatly appreciated.

Not sure but hopefully you can do this using CEL and therefore not require fortran. It is just a matter of putting the coeff. of restitution as a function of particle temperature.

Thank you, but I'm still a bit lost.
Would this mean creating an expression close to

if( particle.Temperature>1000 [K], restitution coefficient==0, restitution coefficient==1)

?

I'm trying to find the answer in the CFX help, but haven't been able to. It says that the restititution coefficient is an available variable in CEL, but I can't see it anywhere.

or would it be as simple as to create an expression

MyExpression = if(particle.Temperature>1000[K], 1, 0)

and then writing MyExpression in the restitution dialog? I tried this but got the following error:

"The parameter "Parallel Coefficient od Restitution' in object .... is defined to be "Single valued" but it depends on the following field valued variables: , particle.Temperature".

Some variables can only be fixed values. I fear you have found one which can only be a fixed value. I would talk to your support office if there is away around this, otherwise you might need to do this in fortran.

CFX allows CEL for coefficient of restitution!

CCTech_Pune, please explain more if you know.
I tried if(particle.Temperature>1000[K], 1, 0), but that didn't work. Then I get the error message written in my previous post.
However, it works if I instead write something like ave(particle.Temperature)@BLADE or something like that, but that doesn't give us what we want I think? We want the temperature of each single particle, not an average (or max, min etc..).

Also, do you know if it's possible to do the same kind of thing in a transient run, using Stick-to-Wall? Stick-to-Wall forces all particles that hit the wall to become part of the wall film, but can this also be conditioned somehow? Not familiar with fortran so I don't really know how much we are allowed to modify.

Hi

I am checking for the same. I will update you.

Thanks