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Optimum inlet velocity

Optimum inlet velocity

Optimum inlet velocity

(OP)
Is there any software or formula to calculate the optimum velocity for water to swirl with out any vortex in a tall and larger diameter tank ?

Thanks

RE: Optimum inlet velocity

Hummm.... swirling and vortex means pretty much the same thing in my dictionary, so on that basis, no.

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

RE: Optimum inlet velocity

Maybe rotation without creating a vortex in the tank could be what the OP is asking - as for a formula noevil  

RE: Optimum inlet velocity

What's rotation without a vortex?  What's a vortex without rotation?  smile

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

RE: Optimum inlet velocity

Rotation w/o vortex = solid body rotation.  I.e. put the tank on a turntable?

RE: Optimum inlet velocity

(OP)
Sorry I could not finish the reply. If you look at the file, I am looking for circular motion with flat surface without a deep vortex to keep the floatables on the surafce swirling without moving toward the center fast.

Thanks and sorry for the confusion

RE: Optimum inlet velocity

What's providing the circular motion?  The sketch doesn't show this.

Good luck,
Latexman

RE: Optimum inlet velocity

(OP)
Ok. Attached please see two model.The force for the circular motions comes from a pump feeding the pipe attached tangentially at the bottom. The water comes in at the bottom and raises to the top to enter the inner funnel. But looking for a flat aurface at the top without a  spiralling conical vortex.If very fast it makes the vortex but if too slow the circular motion may be too slow and may not work well.
There must be some kind of model for this flow.
Thanks

RE: Optimum inlet velocity

IR, What's solid about this setup?

Increase the diameter as you move vertically to increase unit tangential flow area, thereby reducing tangential velocity.  But, as the flow moves from tangent to center, it will likely increase velocity in the radial direction. Can you provide a sloped dish plate for it to climb and thereby slow it down as it moves to the center.

**********************
"Pumping accounts for 20% of the world's energy used by electric motors and 25-50% of the total electrical energy usage in certain industrial facilities."-DOE statistic (Note: Make that 99% for pipeline companies) http://virtualpipeline.spaces.live.com/

RE: Optimum inlet velocity

(OP)
Thanks for the tips. I can try the sloped dish. I used some baffles, called vortex breaker and helps a little.

RE: Optimum inlet velocity

Did you attach the baffles to the reject zone standpipe or the walls of the vessel?  I know agitated vessels use 4 baffles @ 90 degrees on the vessel wall to minimize swirl.

Good luck,
Latexman

RE: Optimum inlet velocity

Umm.  I was not wholly kidding about solid body rotation, where tangential velocity is proportional to radius (vortex is when tangential velocity of flow is inversely proportional to radius).  Use a rotating baffle.  Doesn't have to be driven, just free to rotate.

RE: Optimum inlet velocity

Sounds like you don't want swirling on the surface.  Do you want swirling to some degree beneath the surface?  If so, baffle the tank from about halfway and go up above the surface.

Good luck,
Latexman

RE: Optimum inlet velocity

(OP)
Yes. I want swirling on the surface but want to keep it medium speed without any slope towards the center.

The baffles were attached to the accept zone and the wall. The reject funnel or the zone is not an issue.

I have a video file but could not upload (6.8 MB) for some reason. I get the following message

Cannot find http://files.engineering.com/upload.aspx?referrer=http%3a%2f%2fwww.eng-tips.com DNS Error - Server cannot be found

Sponsored ResultsEngineering Files
  

RE: Optimum inlet velocity

If you have rotation of the fluid mass, the surface cannot stay flat. Your PowerPoint model has several wrong assumption about fluid flow. Conservation of momentum is the guiding principle. You show feed coming into the tank tangential at the outer diameter of the bottom, then a uniform flow upwards. That will not happen. The feed will stay at the wall and you will get stagnation towards the center-bottom.  

RE: Optimum inlet velocity

(OP)
True. It will tend to be stangant at the center. That;s why I extract the accept from the center.


 The swirling motion helps eliminate motorized skimmers and associated equipment.
Once the fluid enters the cell tangentially, the fluid start going towards the center after the first circle and keep following towards that path till it hits the center pipe. You are right and the velocity goes down significantly. As long as it does not stay still and occupy space it is ok for this process.


Thanks

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