Ventilation - Exhaust diffusers

[sahar.rubin]

hi!

i've been simulation exhaust threw ducts in a parking area and i don't know how to control the airflow volume threw a diffuser??

if i just put the bounary conditions outside at the end of the duct, i don't get the amount i require (and i can't get too detailed with the ducts because it makes geomatric problems..)

what should I do???

[derrek.cooper]

Hello. I think there are a few options. If you post an image of what you are trying to do, it may help the group provide better direction. 

Based on what you explained, you would apply the flow rate that is going through the system to a place upstream of the diffuser itself. Likely on an inlet etc. you would then apply an atmospheric pressure condition on the outlet (P=0).

Then you would want to ensure that the diffuser is modeled as its own part, likely a block or a disk depending on the duct geometry. Then apply the appropriate loss data (k-factor, loss curve) to the resistance ensuring you take care in choosing the flow direction. After that, once you run the model you should see the pressure loss due to the "resistance"

Im not sure I understand the geometric problem you mention. So, perhaps the above advice wont help and you may have to contact support to look at your model. 

[sahar.rubin]

i wanted to attach the file but it is too big...

is there a way to send it to you?

by geometry i mean that the ducts aren't real by plan because it makes geometric issues with the software..

i want to make a natural inlet threw the ramp (built a big cube that simulates it) and outlets threw the diffusers, how can i do it?? what pressure should i apply to the inlet/outlets? and how can i control volumetric flow? (didn't really understand what you wrote 🙂 )

thanks!

sahar