Can a fan or prop handle high pressure and volume for a 12 inch plenum?

[Dave Friesen]

I am trying to figure something out and having a lot of difficulty. I would sure appreciate some help. I have a situation where I will need either a fan or a prop. It will need to build up 10-20 lbs of pressure in a plenum but will also need to be able to provide a constant force a large amount of air through a 12 inch hole in the plenum. I will, therefore need a high volume, high pressure unit, no? Is something like that even possible? I am just a Joe Smook with no high edumacation like most of you folk. Would anyone be willing to help me with this? Thank you in advance. Dave

 

[russ_watters]

Welcome to PF!

That's a huge amount of power that you're talking about;. Thousands of horsepower. What is the purpose of this? Supersonic wind tunnel?

 

[WhatIsGravity]

10-20 psi of air through a 12" opening? Are you sure your specs are right? I'm with Russ, what are you doing? I'd think you'll need a million dollar jet turbine to get those kind of volumes, pressures, and flows.

 

[JBA]

I agree with both of the above. Please give more information about your application. In engineering: More and better information = More and better help

 

[insightful]

For example, if your 12" opening leads to a 12" duct designed to a pressure drop of 1" water/100' length, you're at about 2000 acfm (4000 cfm inlet). For 15 psi, you can use a Roots-type blower:

http://www.pdblowers.com/pr13408-roots-ram-x-model-800.php?c=76

Or a Spencer-type multi-stage centrifugal blower:

http://www.spencerturbine.com/products/blowers/multistage-fabricated-centrifugal-blowers/

 

[Dave Friesen]

Thanks very kindly for the replies. I am told I can not state what it is for at this time (my apologies), but it is not a super-sonic air tunnel. This, however means that I would have to significantly reduce the size of the outlet duct or be satisfied with a considerably lower pressure. Am I correct in this?

 

[Dave Friesen]

If I had a couple of 1 or 2 inch outlets, would they be able to produce any kind of thrust?

 

[insightful]

If I had a couple of 1 or 2 inch outlets, would they be able to produce any kind of thrust?

Thrust? You might start here:

https://en.wikipedia.org/wiki/Thrust

 

[Baluncore]

It will need to build up 10-20 lbs of pressure in a plenum but ...

Is that pounds per square inch or pounds per square foot ?
That only makes a scale factor of 144 in the question.

 

[russ_watters]

Thanks very kindly for the replies. I am told I can not state what it is for at this time (my apologies), but it is not a super-sonic air tunnel. This, however means that I would have to significantly reduce the size of the outlet duct or be satisfied with a considerably lower pressure. Am I correct in this?

Unfortunately, that's a question you must answer, not us. Only you know what your requirements and resources are. If you won't tell us the application, can you tell us what the maximum horsepower that is feasible for you to deploy? You are implying but didn't actually say that thousands is too much.

If I had a couple of 1 or 2 inch outlets, would they be able to produce any kind of thrust?

Certainly. But if "thrust" is what you need, this probably changes things because it implies that this device is part of a vehicle that moves. I'm liking WhatIsGravity's jet engine idea. And it the OP you just said "hole in the plenum" -- can it be a nozzle? Because a nozzle works better than a sharp hole for producing thrust.

We really can't provide much useful help here without knowing what the point of this query is and what the constraints are. If this is part of a serious project, you are probably best off to hire an engineer and make that person sign a non-disclosure agreement.

 

[dragoneyes001]

the other thing that can change things drastically is how much back pressure is likely? as in a hovercraft you have the skirt supporting pressure being exhausted.