Simulation of Helical coil using VOF

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snr1 posted this 06 March 2019

I am trying to create a structured mesh for a helical coil in ICEM CFD. But I was not succeeded. Later I shifted to unstructured mesh generation in a workbench. While doing so, I have created inflation layers with first layer thickness. But inflation is not created and it shows "Hard edges are not supported and may be ignored for pre-inflation, please check your model carefully."  How to resolve it?

 

Is it possible to generate a structured mesh for a helical coil in ICEM CFD? if so, can anybody help me?

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kkanade posted this 06 March 2019

as ansys employees we can not download attachments. can you please insert some zoomed in images of your geometry. 

in general, icem can be used for hex mesh in helical geometry. 

for your geometry, go to dm, then use tools - repair - hard edges. then go to meshing and create tet mesh with inflation. 

if this helps you, please mark this post as 'is solution' to help others on forum.

 

 

 

snr1 posted this 06 March 2019

                                              DOMAIN

 

How to generate structured mesh for a helical coil in ICEM CFD? please help me.

 

AND i tried to repair the hard edges in DM, but it has given following.

rwoolhou posted this 06 March 2019

If you sweep the body in Workbench (ANSYS) Meshing does it work? That'll give you an unstructured hex mesh, and you can inflate it too. Probably easier than trying to block the body manually in ICEM CFD. 

snr1 posted this 06 March 2019

Tq sir, but for hexa mesh, inflation is not working. I created geometry in SolidWorks and imported into a workbench. Can you suggest any alternative?

rwoolhou posted this 06 March 2019

Set the body mesh to sweep and set a manual source. Then inflate the sweep method (right click on the tree entry): sweep inflation is applied to the source face from the edge(s). 

snr1 posted this 06 March 2019

Tq sir, i will try it and let you know the result. How to control number of layers in this method with required y+ value?

rwoolhou posted this 06 March 2019

Same as any inflation method: it's just applied slightly differently. 

kkanade posted this 07 March 2019

for such geometry, sweep may not work in one go. 

you may need to split the geometry in few bodies. 

e.g. split 360 degree into 4 bodies of 90 degrees. 

then use sweep method. 

snr1 posted this 07 March 2019

What is the best and simple method to generate a mesh for the above helical coil?

rwoolhou posted this 07 March 2019

I'd sweep it. 

snr1 posted this 07 March 2019

What is the best and simple method to generate a mesh for the above helical coil?

snr1 posted this 09 March 2019

Can anybody suggest, What is the best and simple method to generate a mesh for the above helical coil?

kkanade posted this 11 March 2019

this is already mentioned by rob and me. you will need to use sweep method. 

snr1 posted this 11 March 2019

Okay tq sir for your reply

snr1 posted this 11 March 2019

But the problem is inflation option is not working once we sweep the mesh. But i want to make inflation layers to capture the near wall effects. So, how to proceed further?

rwoolhou posted this 11 March 2019

Inflation for sweep is set slightly differently. 

Set up the mesh method for the zone as Sweep and set a manual source face (one end of the coil). 

Once the sweep method is set, right click on the sweep method in the tree & inflate this method. 

Apply the inflation to the end face & perimeter edge. 

 

You may need to adjust the number of layers & cell size as it's quite a small diameter so inflation may give a poor mesh if you don't get the sizing right. You're also aiming for an aspect ratio of 1-2 up the tube to get the VOF interface correct: you may find the cell count is very high so may need to reduce the length of the coil. 

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snr1 posted this 11 March 2019

nice the sweep method is set, right click on the sweep method in the tree & inflate this method.  Apply the inflation to the end face & perimeter edge.

 

I didn't understand this. If your mind can elaborate clearly

 

thanks for your patience.

rwoolhou posted this 11 March 2019

Watch this video from about 4:40   

 

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snr1 posted this 12 March 2019

Tq sir, i got it

kkanade posted this 13 March 2019

if this helped you, can you mark this as 'is solution' to help others on forum. 

snr1 posted this 13 March 2019

Tq sir, I was able to develop good mesh by using sweep method. Greatly appreciated for your help

snr1 posted this 15 March 2019

Dear sir, if I run without UDF, it results floating point exception error and temperature limited in 20 cells of zone1. How to resolve these issues?

 

Actually, I am simulating the water evaporation process in the helical coil. The boundary conditions are

inlet: water (100%) with mass flow rate inlet and temperature (370K)

wall: constant temperature (500K)

outlet: outflow

operating conditions: 101325 Pa and 300K

saturation temperature in the evaporation and condensation model: 373K with 0.1 frequency.

model: VOF implicit with implicit body force

 

rwoolhou posted this 15 March 2019

Let's keep the mesh here & solver stuff here   https://studentcommunity.ansys.com/thread/mpi-error/   so I'll move the last post & lock. 

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