Max flow through a pipe

mercredi 30 juillet 2014

1. The problem statement, all variables and given/known data



What is the maximum flow rate that can be seen in a water pipe where city water is supplied to a building. The pressure behind the water is 50psi, and the inner diameter of the pipe is 2".





2. Relevant equations

bernoulli's principle





3. The attempt at a solution



I am more over verifying that my process is correct in solving this. I assumed no pipe losses. I used the bernoulli equation. The first point of the bernoulli equation I estimated as the surface of a pond, ocean, or some infinite water source where v=0 (the water elevation does not change) to cancel out the velocity term for point 1. The pressure on top of the surface is 50psi.



The elevation for both points I assumed to be equal, which cancels out all terms for point 1 other than P/density.



For point 2 I used the exit of the pipe where the fed water is first exposed to the atmosphere (p=0). Since the elevation is the same this leaves only the following equation:



Pressure_1/density=V_2^2/2

V=Q/A

therefore

Pressure/density=(Q/A)^2/2

The only unknown in this equation is Q, so it can be solved for.



My question is: is this a valid solution if I am ignoring pipe losses?





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