Hydraulic preference
Hydraulic preference
(OP)
Hope someone can help here. We recently did a flow test on a drain line by connecting it to a tanker filled with water. The tanker had 2 compartments each open to atmosphere and each with its own control valve. A hose was connected to each of the compartment and rolled out down a hill to a 'Y' piece which was then connected to the single drain line. What happened next was not expected. Both valves at the tanker were opened and water allowed to flow, but rather than the tanks compartments emptying together, one emptied fully before the other started. Its like it was give preference. Now I do remember reading something in the past, but its gone. A pointer would be great.





RE: Hydraulic preference
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"The problem isn't finding the solution, its trying to get to the real question." BigInch
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RE: Hydraulic preference
RE: Hydraulic preference
then other idea coming to mind is that one flow stream in a way serves as higher velocity carrier stream due to geometrical trajectory and
sucks-in other flow stream thus iducing faster rate draining of second stream taking place and
utill and unless this drain-out completes first other draining does not take any real effect!
Just hypothetically envisaged case might prove helpful!
Best Regards
Qalander(Chem)
RE: Hydraulic preference
**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Hydraulic preference
RE: Hydraulic preference
**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Hydraulic preference
The only way that I can see this happening is if there is a vapor lock. If tank A is opened first and its water flows down towards the Y-piece, the water will try to flow up the line to B as well as down the drain pipe. The degree to which the water from A will flow up the line to B will of course depend on the pressure drop in the line beyond the Y-piece.
Depending on the geometry of the line, the vapor trapped in the B line can stay there, even after the B valve is opened. We've all seen this happen. The water from B has to flow through the trapped air, which effectively functions as a restriction in line B because the water cannot fill the line at some point. Once the water from A stops flowing there will be no pressure drop after the Y-piece and the pressure available to flush out the trapped air suddenly increases and tank B starts to drain.
I suppose the way to test this is to open valve A and establish flow. Then close the valve at the end of the drain line and close valve A, leaving the A line full of water (no trapped air). Now open valve B and then the end of line valve to establish flow from B. Finally open A again and see if both tanks drain equally.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Hydraulic preference
RE: Hydraulic preference
Will Chevron Corp.
RE: Hydraulic preference
**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Hydraulic preference
Bernoulli tells me the total head has to be the same in both legs. In the left leg the static head has been converted to velocity head to satisfy Bernoulli's requirement that the total remain constant. The static head on the left should therefore be less than on the right. This is how a venturi ejector works. If anything, the flow from the right should be sucked into the Y-piece.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Hydraulic preference
How would you explain the "experimental" results?
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"The problem isn't finding the solution, its trying to get to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Hydraulic preference
I tried to do the twin sink experiment in my kitchen, and I got an intermediate result. One sink did drain slightly faster than the other, but my drain piping is not symmetrical and the sink with the more direct piping drained faster.
@makeup - is there any chance of redoing the experiment the way I described in my post of April 21?
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: Hydraulic preference
as they are finally almost converging to
my 'humbly envisaged scenario' in 20th April 2010 2:41 AM post!
Best Regards
Qalander(Chem)
RE: Hydraulic preference
**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Hydraulic preference
Best Regards
Qalander(Chem)
RE: Hydraulic preference
a star for you ... mostly because I think the "little pink (or purple) stars are funny.
Feel better?
Patricia Lougheed
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RE: Hydraulic preference
At times,In quite a few past posts,
I observe you to act; as if slight cool breeze making a refresshing/heartening impact
Best Regards
Qalander(Chem)
RE: Hydraulic preference
**********************
"The problem isn't finding the solution, its trying to get to the real question." BigInch
http://virtualpipeline.spaces.live.com/