flow direction

[SloFlo]

Hopefully this will be an easy question for most of you.

80Psi(alpha)
_____\_
/ |__/_____20Psi(beta)
| \
\|/
|
ATM(charlie)

If I connect a 1/4" pipe @ 20psi (alpha) to an 8" pipe @ 80psi (beta) will both fluids exit at "charlie"? Or will there be backflow into the "beta" stream. Please help. thanx

 

[sailoday28]

I understand the fluids to be liquid, non flashing etc.
My approach:
Calculate the total pressure(pressure head, velocity head and elevation) at the point where the fluid is to be injected. This calculation should be based on conditions as if there were no tap for injected flow.

If the calculated total pressure is less that the total pressure of the 20 psi source, there will be flow from the 20 psi source into the line. If the total pressure is greater than the 20 psi (total pressue) than some flow will go to the 20 psi as a reverse flow.

Regards

 

[chicopee]

There will be a backflow in the 20 psi(beta) diagram. A good analogy is an eigh inch pipe connected at a bifurcated connection where one leg is let's say 50' long (representing a 20 psi backpressure) and the second leg 5' long (representing the ATM- Charlie). Obviously, more flow will occur at charlie.