Newbie question: Airflow simulation

Hello everyone,

I must start by apologizing for being a newbie in all CFD-related things.
I have a grasp on how CFD works, and I know what I would like to achieve, however I am not sure how to reach my goal.

I have created a project ( which has one model, used to direct air flow from a 40x28 Delta fan to its destination (3D printing part cooling).
There’s an inlet which splits the airflow towards four outlets, and I am trying to optimize airflow path in such a way that turbulences are avoided as much as possible. The fan which blows air into the model inlet is PFB0412EN-E, which I own, and it has a detailed spec sheet (

Whet I can’t seem to figure out is how to assign input and output on the model. I have followed the first Simscale tutorial, however my model inlet and outlets are not covered with a face, therefore I seem to be unable to properly select the areas air should go through.

I would like some advice around what should I do to achieve this. Do I need to alter the model, close the faces for inlet and outlets?

Thank you in advance for your help!

Hey, welcome to the forum!

Don’t worry, we all started from zero at some point, and had to learn.

Your model contains the solid part that encloses the fluid region. As you will to simulate the airflow, then you need to model the fluid region and not the solid!

You can easily create the required volume with the CAD Edit mode, and a Flow Volume - Internal operation. For details, please refer to this page:

Thank you for your answer. It was very helpful, and I managed to make it work. It’s simulating right now.
It seemed kind of counterintuitive at first, but once I was successful for one time, it makes total sense now. Thank you so much!

One more question, if I may… I would like to make sure I am simulating the right thing. The airflow is generated by a 40mm powerful fan, which I know the specs for, and I want to know how the airflow is shaped through the volume, as well as at the outlets (would like to avoid choke areas, as well as uneven airflow).
I have selected “Pressure Inlet” (181 mmH2O) and “Pressure Outlet” (0) as boundary conditions, hoping I would extract air velocities from the four Outlet openings.
Is that the correct way to proceed?

Thank you once again for your invaluable help!

Hi, I am glad you were able to perform the flow volume extraction and run the simulation.

About the boundary conditions, pressure inlet/pressure outlet are perfectly good, and it should allow you to extract the velocities field inside your model. Perhaps a Result Control Items on the outlets will allow you to find average velocities and flow rates at the outlets:

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