verificatin of simulation pressure too big

[Anonymous]

Hi,

is it conveninet  to verify attached simmulation ?

Some pressure parameters are to big.

CFD 2016

Best Regards.

Stoyan Nikolov.

[Jon.Wilde]

Same model as the other thread right?

You need to change your geometry to have a longer (uniform cross section) inlet and outlet. Take the diameter x5 and make that the length of these extensions.

Mesh it far finer and run a 2D axisymmetric model, there appears to be no reason to use 3D here. 2D is FAR faster.

Use Advection Scheme 5 for a pressure driven analysis (or compressible) so you need it either way here.

Is this a compressible analysis? 

If so:

You need to properly constrain your inlet with a Total Pressure (calculate this) and I would also think a Temperature.

Then within 'Solve', you need to assign a Total Temperature.

CFD cannot possibly know enough to define a density at the inlet right now, which it will need to establish your mass flow rate (one of the few constants).

Are you comfortable working these out? They are typically different to static values.

Hope that helps,

Jon

[Anonymous]

Is it k t bother for this simulation ? 

Maybe one more.

Same.

[Anonymous]

Mre specific total pressure.

[Anonymous · Accepted solution]

[Anonymous]

It is compressible.

30 Celsius temperature in "Solve" section.

"Take the diameter x5 and make that the length of these extensions."

Is it also de laval nozzle apply ?

[Anonymous]

thats perhaps the last one (attached)

[Jon.Wilde]

Have a look in our help here, you need to properly calculate the Total T and P.

Yes, also extend the inlet and outlet for this model, it will help 🙂

Keep refining the mesh too, if the results are not smooth and seem to follow the lines between the elements, you likely need more mesh.

Hope that helps!

Jon