SimScale CAE Forum

Determining boundary conditions

Would like to ask to find out the best way to measure the volumetric flow rate (m3/h) of air through a main entrance (sliding door) into the office whenever the door opens/closes. Appreciate help as I have very little background info on this.

I am trying to define this boundary conditions for a Computational Fluid Dynamics (CFD) simulation of airflow into the office.

As it is, the entire office is cooled by only Ceiling Fan-Coil Units and the only source of fresh air is from this main entrance door (sliding door). Hence it is treated as the necessary outdoor fresh air.

Can I say that when the sliding doors opens, the following movement happens (in the picture) and I can measure the volumetric flow rate by measuring the:

  • Air Velocity (by standing at the door when it opens, I have a Kestrel K5400 equipment that can measure velocity)

  • Area of the sliding door (treating it like an air duct)

Extra Assumptions/Information:

  • I’d like to assume that the airflow at the gap between the ground and the base of the sliding door is negligible.

  • I’d like to assume the following convective heat transfer below and fresh air enters as a result of convective movement of air between the colder indoor air at 24 degrees C vs the outdoor indoor at 30 degrees C. Hence, the cold air leaves via the bottom and hot air moves in at the top. Is this considered as one full air change?

Interesting project!

I am looking for papers or some related simulations, in the meantime, do you have any suggestions here @CFD-SQUAD? :slight_smile:

Best,

Jousef

Thanks. Really appreciate SimScale helping out beginners here. Any luck in finding papers or related simulations?

Hi, I have found a paper like this: https://www.aivc.org/sites/default/files/airbase_12996.pdf Will be discussing this with my Professor very soon but wondering if any simulation has been done before, especially with Fan-Coil Units? Thanks!

I have another question: I’ll be constructing the model in Autodesk Revit and how do I then prepare the human models ? Saw that cyclinders are used as stands-in for simulations on SimScale. In that case, what are the dimensions of the cylinder human models?

Thank you once again.

Hey there!

It doesn’t really matter, for simplification you can use cylinders but we also used other approaches where we use human models: https://www.simscale.com/tutorial-thermal-comfort-of-a-meeting-room/ - I am not aware of norms in this regard but I know for example for crash tests that there have to be standardised models that have to be used for different scenarios (and which you can also buy on the internet :wink: ). A bit of research here might help but if you are free I would probably also go with cylinders.

Best,

Jousef