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Calculating pressure created by fan

Calculating pressure created by fan

Calculating pressure created by fan

(OP)
I have a project coming up and I need some help when it comes to the dynamics of fans and output pressure.

If I have a fan that blows a certain amount (CFM) of free air into a pipe of a certain diameter, how do I calculate the PSI in the pipe and the rate of flow?

I have drawn a diagram:
 

RE: Calculating pressure created by fan


There are graphs for duct friction, expressed in inches wg per 100 ft, for different flow rates and duct dimensions and rugosities.

I can recommend Fan Engineering by the Buffalo Forge Company edited by Robert Jorgensen, as an excellent engineering handbook. It will provide you also with an estimation of entrance and exit losses.

RE: Calculating pressure created by fan

Consider posting in another forum ?

  

RE: Calculating pressure created by fan

(OP)
well I want to be able to put a certain amount of pressure into the the pipe. For example I want the fan to be able to pump 3 psi into a 1 inch diameter pipe or hose. How much cfm would I need?

RE: Calculating pressure created by fan

jerezz,
The way you phrase your problem now it is simply a question of finding the capacity of the 1" pipe.  You will need to define your initial pressure(P1), the final pressure (P2) the length of the pipe (L), the inside diameter (D), etc.
You can use the McQuay DuctSizer program which can be downloaded at the attached link.  

In theory, once you find the capacity of the pipe, you can then select a fan of the same capacity and you will get the pressure drop that you want - under steady state conditions.  In practice, it may not be that easy.  Good luck.

http://www.mcquay.com/McQuay/DesignSolutions/Software

RE: Calculating pressure created by fan

(OP)
so once I have that how do I calculate the pressure increase?

RE: Calculating pressure created by fan


Read well what vzeos has said: P1- P2 is the pressure to be overcomed.

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