Deadheaded fan power requirements

[stresshump]

I am looking to test the fan blades on a fan (12,000 CFM at 150HP) for a life cycle of start and stop cycles. Not nessesary to actually move air for this test as the CF loads on the blades are what folks are concerned about. How can I figure out what HP motor to use (hopefully much less than 150HP) if the fan is "deadheaded".

 

[btrueblood]

I'd think the acceleration forces on the blades during start-up would also be important? That would argue towards having the same motor HP as for the open fan, I'd think, or at least the same initial startup torque.

 

[TheTick]

Your assumption about deadhead being highest stress is based on what? When a fan moves air, power increases (evident in increased motor voltage and shaft torque). The impeller is under stress as it imparts energy to the air.

You may want to run a test or two to check your assumptions.

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[pmover]

at deadhead condition, no mass/volumetric flow. hp consumption to be dependent on mass of rotating fan and air resistance. could be noisy test though. you should contact the fan mfg & obtain the fan performance curve data as this curve/data typically provides you your answer. hope this helps.

good luck!
-pmover

 

[TheTick]

Correction: increased motor current draw

Honesty may be the best policy, but insanity is a better defense.

http://www.EsoxRepublic.com

-SolidWorks API VB programming help

 

[miningman]

12,000 cfm , 150 HP, with an assumed fan efficiency of 80% computes to a staic pressure of 63 inches water guage. Is this really what you are dealing with?? Sounds more like a compressor than a fan.

 

[electricpete]

I'm drawing a blank... what does "CF load" mean?

=====================================
(2B)+(2B)' ?

 

[electricpete]

If it is a fan, do you know if it is radial flow or axial flow?

=====================================
(2B)+(2B)' ?

 

[btrueblood]

e-pete,

I guessed CentriFugal, but we all know what assumptions make us.