Turbulent or Laminar flow in a leaking tank?

[Jarv]

Is there an equation which defines the flow (i.e laminar or turbulent)in a leaking storage tank. The leak is from the tank bottom (carbon steel).

 

[BobPE]

Jarv:

You actually have to solve a double differential equation to get the flow and subsequent time to drain the tank since flow will vary with the changing head. To get a guess, I would use an orifice equation. I would not concern myself with the flow regeim (laminar or turbulent) as it's only a hole in a tank. The orifice equation will give you the flow at a defined head, but you will still have to solve the diff. eq's to get the flows for various heads.

hope this helped....

BobPE

 

[poetix99]

...or simply solve the orifice equation that "BobPE" described for various tank liquid levels and make a piece-wise curve of leak-rate vs. level.

Don't extrapolate from such a curve.

 

[PAN]

In case of laminar flow (assumption), this link is useful.

http://www.vacuuminst.com/sub/fueltankpaper.pdf

 

[JoeTank]

Jarv,
Are you describing a leak thru a bottom that is in contact with the soil or foundation? Or, is it a leak in a suspended bottom such as a tank up on legs?

Steve Braune
Tank Industry Consultants

http://www.tankindustry.com

 

[quark]

WB Bob. So long to see you and we did miss.

Jarv!

If you check out for the condition of maximum fluid height in the tank and at instantaneous flow conditions, then you can decide whether the flow is turbulent or laminar. (if it is laminar at maximum liquid height then it is laminar throughout).

V = Cd(2gH)^1/2 is the velocity equation through an orifice. Use appropriate units and Cd can be in the range of 0.6 to 0.7.

This thread will be a good reference.
thread378-41603

Regards,


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