[allendoss79]

Hello all,

I am planning on meshing a stator and a rotor separately.
Can somebody please tell me how to go about doing it in turbogrid?

I have tried the method used by FAR(turboengineer) on youtube http://www.youtube.com/watch?v=0Qmm9sKQaFc
for the same but I'm unable to generate the flow path.I feel the lack of a root(T section at bottom of blade with grooves) is the reason. Can somebody please tell me how to go about this problem?

I have attached a pic of Ansys DM file: The flowpath in the pic is incomplete.The two yellow lines(layers) in the middle stop midway!..hence i cannot export file to turbogrid.

Also what parameters does turbogrid actually need to mesh? How does it determine the thickness of the blade passage surrounding the blade that it's going to mesh?
Thanks in advance.

[mitra22]

Hi,

To easily generate a turbogrid mesh. Avoid all the exporting business. The best way is to start with making the "CURVE" files. For stator and rotor separately make the HUB,BLADE,SHROUD files. It is very easy to make these files. All you need to do is put the coordinates in a text file and change the extension to ".curve". You may find a sample of the "hub.curve,shroud.curve,blade.curve" files in the tutorials.

Coming to your flow path, donot worry if the blades extend out of the flowpath.Turbogrid will automatically cut-off the blades outside the flowpath.

By thickness of mesh do you mean size of the passage??? If yes!! Then all you need to do is specify the number of blades/blade passages, it will automatically generate a single passage. Required for your analysis.

Also I find that the blade geometry is very very poor. You could smoothen both the stator and rotor blades and avoid sharp edges. Ensure that there are no ups and downs on the PS, SS surfaces of the blades.....

[allendoss79]

Attached 4 pics

[allendoss79]

Originally Posted by mitra22

Hi,

To easily generate a turbogrid mesh. Avoid all the exporting business. The best way is to start with making the "CURVE" files. For stator and rotor separately make the HUB,BLADE,SHROUD files. It is very easy to make these files. All you need to do is put the coordinates in a text file and change the extension to ".curve". You may find a sample of the "hub.curve,shroud.curve,blade.curve" files in the tutorials.

Coming to your flow path, donot worry if the blades extend out of the flowpath.Turbogrid will automatically cut-off the blades outside the flowpath.

By thickness of mesh do you mean size of the passage??? If yes!! Then all you need to do is specify the number of blades/blade passages, it will automatically generate a single passage. Required for your analysis.

Also I find that the blade geometry is very very poor. You could smoothen both the stator and rotor blades and avoid sharp edges. Ensure that there are no ups and downs on the PS, SS surfaces of the blades.....

Hi mitra,

Firstly thank you very much for the reply.Will do as you have suggested. I have a few questions.

1.What exactly are the hub,shroud and blade curve files that turbogrid needs? I have attached 4 pics.

a)Do the points in the "stator_profile_blade" make up "blade.curve" file that you were saying.That is, the cross section of the stator blade midway between hub and the shroud.

b)Are the "hub.curve" and "shroud.curve" files open curves(see white lines in
"2D_hub_shroud")? Or are they in 3D which are obtained using the outer boundaries of the surface in the attached "3D_hub_shroud"?

2.Since Turbogrid automatically cuts off the blades outside the flowpath, so what about the fluid boundary layer created at the hub where fluid velocity is 0? Does turbogrid take that into account?

Thanx again.

[Far]

are you able to do that?

[allendoss79]

Originally Posted by Far

are you able to do that?

Hey FAR,
The method shown in your video works for other geometries.. But doesn't work for one shown in the pic.. Could you please check if the problem is with the designed blade or something else?
Also wat exactly are hub, shroud, profile curve files? Are these on a plane(XY, YZ) or are these in 3D space?

[Far]

It seems you are working on cascade models of stator and rotor!

Hub is the lower profile of blade (at lower raduis) and shroud is upper cover of any turbomachinery. Usually there is gap between blade tip and casing/shroud.

The method i had shown in the video works for all type of geometries. Recently I had presented that in two webinars where geometry was centrifugal compressor

[Far]

Originally Posted by mitra22

Hi,

To easily generate a turbogrid mesh. Avoid all the exporting business. The best way is to start with making the "CURVE" files. For stator and rotor separately make the HUB,BLADE,SHROUD files. It is very easy to make these files. All you need to do is put the coordinates in a text file and change the extension to ".curve". You may find a sample of the "hub.curve,shroud.curve,blade.curve" files in the tutorials.

Yes it is easier method if you have coordinates of blade , hub and shroud in some specified format. As mitra said format is given in the help and you can refer it. Sample files of rotor 37 also comes with turbogrid and you can copy those files and past coordinates of your geometry.

Design modeler is used when you have model in cad format and you want to skip/avoid of step of getting coordinates of that geometry in some other program like Gambit etc.

[allendoss79]

Hey Far,

I was finally able to get the mesh and export to fluent/cfx. the problem was in my geometry in CATIA where in i pocketed an extra amount to obtain the hub and shroud(see the attached file-unnecessary).I didn't know Turbogrid would automatically take this into account.
Thanks again for your help.

[Ahmed Saeed Mansour]

Have you done it sir?