SimScale CAE Forum

Air duct meshing issues


#1

Hello everyone!

I’m currently working on a CFD for an air duct.


https://www.simscale.com/projects/kilian/newflow

but I do get meshing error right after starting: "
Some geometry faces could not be processed in meshing. Please consider cleanup operations in your CAD tool or contact our support for further assistance."

I already meshed the brake disc and the air duct on it’s own with no error:
https://www.simscale.com/projects/kilian/disc_brake_1/
https://www.simscale.com/projects/kilian/schacht/

Any clues? The error message does not help much :face_with_raised_eyebrow:
If I’m meshing both together in one model.
Do they need to have a physical connection?

Many thanks in advance! :slight_smile:


#2
  1. Correct, the mesh must be continuous for your study

2)Unless you want to also simulate the cooling of the disc (in which case you need to switch to conjugate heat transfer sovler) what you need to do is mesh the area around the disc and duct, not the disc an duct themselves. There was another very similar question posted today (link below) and if you read the replies, you will see they explain how to mesh the area around the solid objects.

https://www.simscale.com/forum/t/boolean-operation/86079/2


#3

thanks for the quick response @roy_g! :slightly_smiling_face:

Concerning the simulation of the cooling effect: Yes I would like to do this. I tried some month before with just the disc but I struggled implementing a rotating zone (the disc in that case) within Conjugate Heat Transfer. Do you know if this is even possible?
Idid not find any Public project dealing with that problem


#4

Hey @kilian!

Can you attach any document or link to some research paper explaining the phenomenon you are trying to simulate.
so that we can understand better and help you solve the problem! :slight_smile:


#5

@kilian unfortunately it is not possible to implement a rotating zone for conjugate heat transfer (@jousefm is this something simscale are working on adding?) .


#6

@ojagtap that gives you an overview about the topic:

And the corresponding whitepaper:


#7

hi @kilian,

  1. in your model there was a couple of overlapping parts. I would be recommended, remove that section first.

suggestion:-

  1. there is no option for rotating zone in CHT so, you can split this project in two simulation type. first. perform thermal simulation (calculated heat flex from your vehicle speed and applied). find out, maximum temp. generated on the brake disc.
    read my past work :- "INVESTIGATING TEMPERATURE ON F1 BRAKE DISC AT MONACO GP INCIDENT " simulation project by ROHIT SURYAWANSHI
    NOTE:- in this thermal simulation temperature remove my air not consider.

  2. after thermal simulation, go for CHT where you can perform what you are targeting.

  3. in CHT, you can also add brake pad ( also add in thermal simulation) and applied contact between the brake disc and brake pad.

  4. Applied maximum temp. in initial B.C.
    NOTE:- Considering max. temp. as input because temp should be lower after CHT simulation.

  5. applied your heat flex in Specific power source.

I was also planning to simulate this kind of project (on f1 brake disc).
if you require any help, contact me at any time.
best,
Rohit.


#8

great work @ROHIT_SR with your F1 brake. I will try to adapt your two simulation solution for my model. Will let you know how it worked

And thanks for the clue with the overlapping parts :slight_smile:


#9

I cleaned the model (now built as a single solid), but the error (Some geometry faces could not be processed in meshing.) still exists :weary:

Any clues are highly appreciated.


#10

Please read my first response. You are doing a flow study and so you don’t need to mesh the solids but rather then air volume defined by the solids. Once you get to material selection you will find that the incompressible solver does not even allow you to define a volume as a solid material.


#11

@roy_g yes -
Therefore I’m doing a hex dominant parametric mesh. I placed the material point outside of the solid but within the background mesh box. My intention is to simulation only the flow and no thermal effects. So no material definitions are needed.


#12

So you tried to mesh the flow region and it did not work? Can you upload a step file (post a dropbox or google drive link) to your part so we can have a look in more detail.


#13

@roy_g exactly.

many thanks in advance!! :slight_smile:
https://drive.google.com/drive/folders/1JmrxAwOzWxKdFcLI4KPe7ko-4pM5qIWu?usp=sharing


#14

Your 1 solid body is not watertight.

I show 33 naked edges that need to be fixed:


#15

yes, @DaleKramer was right first to improve your cad model.

condition1:- in your model, there was only one way for flow simulation and it was that air duct. (if you make its watertight). but then there was no meaning of that brake disc.
condition2:- if you want to simulate all part (disc with air duct) than there should have one outer box. or make Cartesian box AND mesh it. ( but than simulation was external)

it was difficult to work on step.file for me. if you make this all part in Solidworks than send SolidWorks file to me.

Best.
Rohit.


#16

Once this is watertight and a good CAD file, I think you could just mesh it all in a Background Mesh Box which gives the relevant air volume mesh and then assign BC’s to the BMB to get external air to flow into, around and thru the duct with a stationary rotor.

Then you could separate the rotor enough to put the rotor into a rotating zone and maybe get a better simulation of what you may want (although I think there are still current limitations of MRF’s that would interfere).


#17

Thanks a lot @DaleKramer and @ROHIT_SR I corrected the model and now it works!!! :slight_smile:

I did the first simulation without rotating zone. Next step will be with MRF.