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Calculation for draining a tank
3

Calculation for draining a tank

Calculation for draining a tank

(OP)
I would like to know the calculation for finding the time to drain a static, atmospheric tank of water to a pit, which is also at atmospheric pressure.  Can anyone help?  Please include friction loss and minor losses.

RE: Calculation for draining a tank

(OP)
Latexman

Thanks for information.  I had looked at the site you gave me, but I was also looking for the actual calculation so that I can check the answers by hand.

RE: Calculation for draining a tank

ROES,
The FreeCalc linh has a reference  to a Chem. Eng. article giving the basis which should fulfill your needs.

Klem                         

RE: Calculation for draining a tank

If you have access to a technical library there are two articles that can be of help:

Chemical Engineering, May 15, 1972 Plant Notebook :"Timing gravity flow from vertical tanks" by E.P. Lynch.

Chemical Engineering, Jan 1989. "Drainig Tanks: How long does it really take ?" by Shoaei and Sommerfeld (with references).

Good luck.

RE: Calculation for draining a tank

YOU CAN READ  FLUID MECHANICS MA GRAW HILL

IN THAT BOOK DESCRIBE TIME DISCHARGE (DRAINING)
PLEASE SEE THAT BOOK

RE: Calculation for draining a tank

Formulas fail when vortices form. A vortex may form when:

-The liquid is falling at a rate of more than 1 m/s
-When the outflowing speed is greater than 3 m/s
-When the level is low
-When the drain connection is located away from the tank   
 walls in large diameter tanks
-When there are large quantities of gas dissolved in the
 draining liquid
-When the liquid inlet induces rotation
-When the liquids are near their boiling points
-When Coriolis effects may somehow influence the flow

RE: Calculation for draining a tank

If vortices are a problem, a simple breaker of two baffles at 90 degrees  attached to the inlet, projecting one pipe diameter (D)above and one D  into the inlet has solved the problem for me. The portion above should be about two D wide.

Klem

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