Formula for GPM ?

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Master Plumber Mark

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thats a good question

I would have to look that one up somewhere. in one of
my old plumbing books...

in plumbing terms I am pretty sure you
would have a ....shi/load of water... comming out the
end of that pipe....






if a tree falls in a forrest and their is no one around
to hear it , will it stilll make a crashing sound???
 
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R

Rancher

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speedball1 said:
Without the friction line lose figured in.

Simple, and you won't like the answer.

Infinite.

Reason, same as if you had a piece of copper wire, X inches long with no resistance, it has no limit to the current it can carry... V=IR, I=V/R opps division by zero, the universe just imploded.

Rancher
 

hj

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gpm

If there is no friction loss, then it will deliver whatever GPM the source can supply. But for a real world answer you would have to include the length of the pipe.
 

Phil H2

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Without calculating all of the conversions

Cu ft per second = 2 x ( cross sectional area in feet²) x sqrt[ (pressure in lbs/ft²) x (acceleration of gravity) / (specific weight)]

gpm = (60 x 7.48) cu ft/s
cross sectional area = PI x (2")² / 144
pressure in lbs/ft² = psi x 144
gravity is 32 ft/s²
Specific weight of water is 62.4 lbs/ft³

This is not very real world because it does not include friction losses, minor losses, or change in elevation.
 
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Jimbo

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You have to include all the variable to get meaninful info.

For 2" sch. 40 PVC, a flow of 50 GPM would see a pressure loss over a 100 foot length, of 1.73 PSI, and the water velocity would be 4.77 feet per minute. Both of these are reasonable numbers, so if you needed 50 GPM through 100 feet of pipe, 2" would be an appropriate size.

Tell us what your goal is. Perhaps we can provide further information.
 
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