[mageno]

Hello!
I’m new in jet fan garage CFD and I have some questions about jet fan system. I will be very happy if you can help me.

I know how to calculate mechanical ventilation (typical canal ventilation), I know how to draw it, „hand” calculate it, make simulations, but physics impulse ventilation are completely different. In my country jet fan is the new type of garage ventilation and we haven’t got any regulations, standards etc.

I read the British Standard, some literatures, guides and many articles in google about jet fan, simulations, calculate and no one want to share exact calculation. I realise that is the specialized knowledge.

I’m looking for “hand” calculation jet fan (impulse ventilation) in the garage. I know how to calculate:
- velocity of smoke at required control distance,
- minimum design flow rate for smoke control,
- mass-flow of smoke and smoke temperature at the fire.

In the FlaktWoods presentation there are writing about:
- mass-flow towards the extract,
- density downstream,
- the extract flow rate required,
- thrust fan quantity,
- CFD.

I think I will not have big problems with CFD (I don’t make it in Ansys, but Pyrosim which I know one). I think I can calculate thrust jet fan too, but I have problems with finding the other points.

Could you give me some advises where I can find that missing calculations, please? I will be very thankful for that.

I am writing now my thesis for my university and I think I made the worst choice ever, because I can’t find some calculation – need documents proof . I have got almost all theories about jet fan system and fire scenarios in my garages. Unfortunately I’m stuck on calculations, without calculation = no simulation.

Two weeks ago I thought this all calculations about jet fan are experimental in CFD, but I found FlaktWoods presentation and since then I can’t find nothing new. I wrote to FW in my county but they don’t share course materials about jet fan for students.

Thank you for helping me!

Best regards,
Mageno

[DaveyBaby]

Hi Mageno!
Just to clarify, what do you need the hand calculations for?

Are you focussing on the jet fan itself, and studying a CFD model of it, or studying a smoke filled room with a jet fan with known properties providing an outlet boundary condition?

Do you need something to help define reasonable boundary/initial conditions as input to the CFD?
Or benchmark the CFD against the hand calculations?
What quantities do you need to calculate, and where?

Kind Regards,
David

[prom]

Hi,

I use DesignBuilder. Is it possible to do jet fan simulation in garage using DesignBuilder? Is it correct approach to give only give jet fan details for simulation or do I need to give supply and exhaust flowing in and out of the building Or is it enough to give jet fan cfm to see the flow inside the parking area? Please help.

-Prom

[Paul Caicedo]

Hello,

It's possible to simulate jet fans in DesignBuilder with the circulation fan icon.
https://designbuilder.co.uk/helpv7.0...culation%20fan

Paul