ICEM Meshing of Helical Finned Tube

ammarali311 · December 4, 2018, 12:53

Hello, I am working on a project for calculating pressure drop and heat transfer characteristics of internal helical finned tube. The dimensions of fins are very small as compared to the tube diameter. Hence they are called micro-finned tubes. I am having a difficulty in meshing the geometry in ICEM. The procedure that I am following is this
1) Import CAD model in ICEM.
2) Generate a 2D Surface Blocking of the inlet surface.
3) Meshing the 2D Surface Blocking using Pre Mesh Edge Parameters.
4) Extruding the 2D Blocking Mesh Surface along the helical curve of the fin to the outlet.
The problem is that I am not getting a good quality mesh using edge parameters. I need dense mesh at the fin boundaries and walls of the tube for accurate results and then from there the mesh density should decrease to the center of the tube because gradients are not very important at the center. But I am getting very dense mesh away from fins and walls which is making number of elements very large. Maybe I am not using efficient blocking for mesh distribution, I don't know. Can anyone help me in meshing this geometry. Thanks
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Gert-Jan · December 4, 2018, 16:10

I would:
1. extrude your geometry (with fins) to a small extent (0.1xD) upstream your inlet.
2. create a bodypoint here
3. create a tet mesh (Octahedral/robust) in this volume (not the large one downstream)
4. Create prisms on the outerwall (including fins) of this volume
5. Smooth the mesh.
6. Select only the elements on the inlet and extrude these along the fins of your larger volume.

ammarali311 · December 5, 2018, 11:38

Quote:

Originally Posted by Gert-Jan

I would:
1. extrude your geometry (with fins) to a small extent (0.1xD) upstream your inlet.
2. create a bodypoint here
3. create a tet mesh (Octahedral/robust) in this volume (not the large one downstream)
4. Create prisms on the outerwall (including fins) of this volume
5. Smooth the mesh.
6. Select only the elements on the inlet and extrude these along the fins of your larger volume.

How can I extrude the geometry upstream? And what is meant by bodypoint? I am new to ICEM so don't know the terminologies.

Gert-Jan · December 5, 2018, 15:50

- Your geometry is clearly a Spaceclaim geometry. There you can create a small slab upstream your inlet.
- you have to tell ICEM where you want a volume mesh. You should do this by creating a body point inside your volume. In this case the thin slab. This is really basic of ICEM. If you don't know this, then I refer you to the tutorials.

December 4, 2018, 12:53	ICEM Meshing of Helical Finned Tube	#1
ammarali311 New Member Ali Join Date: Oct 2018 Posts: 8 Rep Power: 7	Hello, I am working on a project for calculating pressure drop and heat transfer characteristics of internal helical finned tube. The dimensions of fins are very small as compared to the tube diameter. Hence they are called micro-finned tubes. I am having a difficulty in meshing the geometry in ICEM. The procedure that I am following is this 1) Import CAD model in ICEM. 2) Generate a 2D Surface Blocking of the inlet surface. 3) Meshing the 2D Surface Blocking using Pre Mesh Edge Parameters. 4) Extruding the 2D Blocking Mesh Surface along the helical curve of the fin to the outlet. The problem is that I am not getting a good quality mesh using edge parameters. I need dense mesh at the fin boundaries and walls of the tube for accurate results and then from there the mesh density should decrease to the center of the tube because gradients are not very important at the center. But I am getting very dense mesh away from fins and walls which is making number of elements very large. Maybe I am not using efficient blocking for mesh distribution, I don't know. Can anyone help me in meshing this geometry. Thanks p1.PNG p4.PNG p5.jpg p6.jpg p7.jpg

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December 4, 2018, 16:10		#2
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,827 Rep Power: 27	I would: 1. extrude your geometry (with fins) to a small extent (0.1xD) upstream your inlet. 2. create a bodypoint here 3. create a tet mesh (Octahedral/robust) in this volume (not the large one downstream) 4. Create prisms on the outerwall (including fins) of this volume 5. Smooth the mesh. 6. Select only the elements on the inlet and extrude these along the fins of your larger volume.

December 5, 2018, 15:50		#4
Gert-Jan Senior Member Gert-Jan Join Date: Oct 2012 Location: Europe Posts: 1,827 Rep Power: 27	- Your geometry is clearly a Spaceclaim geometry. There you can create a small slab upstream your inlet. - you have to tell ICEM where you want a volume mesh. You should do this by creating a body point inside your volume. In this case the thin slab. This is really basic of ICEM. If you don't know this, then I refer you to the tutorials.