vortex at the tank outlet 1

[prens11us]

Hello All,

I need to get some sources about the theory of the vortex formation at the tank outlet and vortex breaker design to prevent the vortex.

The tank is a 21 meter height and 92 m diameter crude oil tank.

Outlet pipe is 48".

There are some formulas which is related with froude number and swirl number. I put a device at the outlet of the tank to decrease the froude number to prevent vortex formation.



Thanks in advance...

 

[sshep]

I think pump manufacturers are a good source of general guidelines for suction piping design. All the major companies have technical recommendations for this. For example:

http://www.gouldspumps.com/pag_0006.html

Another common reference, the Durco Pump Engineering Manual, also gives a submergence vs velocity chart but does not include details on vortex breaker design.

best wishes,
sshep

 

[MJCronin]

prens...

In what country is the tank located ?

 

[prens11us]

It is located in Azerbaijan. I look at the formulas in

http://www.gouldspumps.com/pag_0006.html.

but I guess these are for water. can I find a formula for crude oil.

 

[roker]

hello,

if you did put a voetex beaker according to what design? did you have problems in pump suction (cavitation?).

is the outlet nozzle located at bottom or side of the tank?

also if you keep some level in the tank you will not have vortex formation.

did you know that the direction of the vortex swirle depends if the tank is located in the north or south of the globe?

regards,
moshe

 

[DiegoMartinez]

Hi Moshe,

Can you explain a bit more about this, please?

"did you know that the direction of the vortex swirle depends if the tank is located in the north or south of the globe?"

 

[panduru]

@London2002:

This may interest you:
The Coriolis Effect - Wild Weather

http://www.abc.net.au/northcoast/stories/s1000270.htm

@roker:
There is something on tanks, too in the above article.

 

[IFRs]

In a previous life, I designed and installed hundreds of suction line diffusers for use under floating roofs, many in crude oil tanks. We used perforated plate or pipe with holes or slots. Never did any calculations for vortex breaking, just installed them for 25 years with no problems. You "may" be over thinking a problem that has a simple solution.

 

[panduru]

This thread may be of some use:

http://www.eng-tips.com/viewthread.cfm?qid=155996

 

[epoisses]

The north/south side of the globe story leading to different direction currents (e.g. at home in the washbasin) is an urban legend as fas as I know -- at least if that very fact is not an urban legend. I have never seen any feature on a vortex breaker related to the vortex being clockwise or anti-clockwise.

 

[BRT549]

A simple vortex breaker design - build a cross out of metal plate and install inside the inlet pipe. It should be 1.5 times longer than the pipe diameter, so about 72 inches long. Let about 1/3 of it stick out into the tank, but no more than that. Doesn't matter which direction it swirls. There are other designs, but this is the simplest.

 

[wfn217]

This article may be of interest:

http://kfki.baw.de/fileadmin/conferences/ICHE/2000-Seoul/pdf/201/PAP_233.PDF

 

[MJCronin]

pren,

Sombody else has studied this:

http://journals.pepublishing.com/(p...,101,102;linkingpublicationresults,1:119771,1