I'm doing calculations for how much water was lost during flushing a hydrant. It is a 2.5 in. outlet and the pressure is on the system in that zone is 40 psi. It was flushing for 1.5 hours.
Q=AV
V=[(2 dP gc)/density]
density = 62.4 lb/ft^3
dP=40 psi
gc=32.2 lbm ft / lbf s^2...
Yeah... I think my problem was too many assumptions, and trying to use Bernoulli's formula with very basic assumptions. I ran some numbers taking into account friction, length of pipe and some other stuff that I didn't take into account at the beginning, using the Darcy Weisbach equation. Now...
You're right.. but remember I have mass flow going in from one end, and mass flow going out from two ends, that will be:
A1v1=A2V2+A3V3 (all that goes in, goes out)
At the inlet, I have 20 gpm going in (0.0445 ft^3/s), and at a 3/4" that's a velocity of 14.35 ft/s.
Now, if I take into...
Well... I'm taking water as an incompressible fluid, and density will be constant. I don't think density would affect a lot on the calculations, would it?
Let's say that we have a 3/4" copper line to supply water. We have a volumetric flow of 20 gpm (0.0445 ft^3/s). With this, we have a velocity of 14.35 ft/s. Now, at the end of the copper line, I want to service two homes, so I split the service. Comming out of the 3/4" copper line, I have...