[oozcan]

Hi all,

I am working on 3d heat exchanger in order to view heat transfer and flow

you know that mesh is the most important to evaluate the results.

I have tried a variety of types of mesh but some values are awful like skewness

Attached photos show mesh ( only inflation) .First one shows mapped face meshing in symmetry plane.The other one is inflated in inflation mesh

Is there any methods you suggest?

Kind Regards,

[Far]

Originally Posted by oozcan

Hi all,

I am working on 3d heat exchanger in order to view heat transfer and flow

you know that mesh is the most important to evaluate the results.

I have tried a variety of types of mesh but some values are awful like skewness

Attached photos show mesh ( only inflation) .First one shows mapped face meshing in symmetry plane.The other one is inflated in inflation mesh

Is there any methods you suggest?

Kind Regards,

This mesh seems ok to me. Go ahead and run simulation.

[oozcan]

Originally Posted by Far

This mesh seems ok to me. Go ahead and run simulation.

Hi far,

Thanks a alot to reply my post.

But skewness still is above 0.98 and I am still working on it.

Kind Regards,

[hwet]

you can actually see the cells where the skewness is terrible, then decide what to do to improve it.

[Kapi]

check whr you have high skewness and apply sizing thr.
try to make fine mesh at critical points and regions with high skewness!

[siqma]

Originally Posted by oozcan

Hi all,

I am working on 3d heat exchanger in order to view heat transfer and flow

you know that mesh is the most important to evaluate the results.

I have tried a variety of types of mesh but some values are awful like skewness

Attached photos show mesh ( only inflation) .First one shows mapped face meshing in symmetry plane.The other one is inflated in inflation mesh

Is there any methods you suggest?

Kind Regards,

How many elements does your mesh have?
I am working on a flow in shell side of a heat exchanger and it has bout 240 tubes and 5m length so I can`t mesh it because when I use inflation method it has maybe about 110,000,000 elements.How can I reduce it?

[oozcan]

Originally Posted by Kapi

check whr you have high skewness and apply sizing thr.
try to make fine mesh at critical points and regions with high skewness!

Thank you for your help Kapi and hwet

sizing thr ?, what does it stand for ''thr'' ?

Please could you see the photos last mesh situation in attached?

I have used inflation and mapped mesh rather than using sweep or multizone ( because there are 28 tubes and I dont know how can I mesh all tubes in multizone and sweep)

ELEMENT : approximately 8 millions
NODES : approximately 3 millions

Skewness shows that in that attached photo is 0.96 bla bla bla but now 0.9503 bla bla
Kind Regards,

[oozcan]

what should max skewness be ? 0.89 ? I have decreased it at most 0.949995 bla bla .

[Kapi]

sometime going to help section and looking for answer is better!!

From Ansys help:

The following table lists the range of skewness values and the corresponding cell quality.

Value of Skewness Cell Quality
1 degenerate
0.9 — <1 bad (sliver)
0.75 — 0.9 poor
0.5 — 0.75 fair
0.25 — 0.5 good
>0 — 0.25 excellent
0 equilateral
According to the definition of skewness, a value of 0 indicates an equilateral cell (best) and a value of 1 indicates a completely degenerate cell (worst). Degenerate cells (slivers) are characterized by nodes that are nearly coplanar (collinear in 2D).

Highly skewed faces and cells are unacceptable because the equations being solved assume that the cells are relatively equilateral/equiangular.

Hope it helps.


Also, try to make your model smaller. Either mirror it or use a sample model to see the effects.

Cheers
KAPI