Large volume laminar flow machine

[karimwassef]

I have a 400gal with surge now. I added powerheads too.

I can move massive volumes of water.

But when I dive, the motion is completely different.

With a maturing stocked tank, I don't have the option to do this perfectly. So, I plan to learn as much as possible and establish proof of concept. I'll do it right on my next build.

This is how I developed my current tank's surge.

For my current tank, I'll have to retrofit my setup as best as I can. That's the goal.

 

[karimwassef]

It's on my main build thread, but here's my engineering drawing

<a href="http://s1062.photobucket.com/user/karimwassef/media/2015view2_zps8uyarupv.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/2015view2_zps8uyarupv.jpg" border="0" alt=" photo 2015view2_zps8uyarupv.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/2015view1_zpsw2xbuw3k.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/2015view1_zpsw2xbuw3k.jpg" border="0" alt=" photo 2015view1_zpsw2xbuw3k.jpg"/></a>

And here are some pics

<a href="http://s1062.photobucket.com/user/karimwassef/media/55D6D60A-5593-4749-8EEF-E50A6B38052A_zpso4ixwwat.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/55D6D60A-5593-4749-8EEF-E50A6B38052A_zpso4ixwwat.jpg" border="0" alt=" photo 55D6D60A-5593-4749-8EEF-E50A6B38052A_zpso4ixwwat.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/0340EEC7-4A5B-40DF-A428-95FF27F8F32A_zpslwpa0sn7.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/0340EEC7-4A5B-40DF-A428-95FF27F8F32A_zpslwpa0sn7.jpg" border="0" alt=" photo 0340EEC7-4A5B-40DF-A428-95FF27F8F32A_zpslwpa0sn7.jpg"/></a>

<a href="http://s1062.photobucket.com/user/karimwassef/media/74E799A6-59B9-4CCE-90DA-30AFF48D0554_zpsty4m3yrf.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/74E799A6-59B9-4CCE-90DA-30AFF48D0554_zpsty4m3yrf.jpg" border="0" alt=" photo 74E799A6-59B9-4CCE-90DA-30AFF48D0554_zpsty4m3yrf.jpg"/></a>

 

[JamesHolt]

Thanks for the pics,, I have a different idea, need to think on it a bit..
I have an old 55 I am not using, I may mock something up this weekend

 

[karimwassef]

I don't think I can push the surge output through a laminarizing box.

The box needs high pressure. A surge is low pressure, high volume.

 

[karimwassef]

This could be achieved with one pump with very high pressure output.

<a href="http://s1062.photobucket.com/user/karimwassef/media/Mobile%20Uploads/0F9F3351-4CA9-416E-9245-72D1D2F6B458_zpswgu1x93o.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/Mobile%20Uploads/0F9F3351-4CA9-416E-9245-72D1D2F6B458_zpswgu1x93o.jpg" border="0" alt=" photo 0F9F3351-4CA9-416E-9245-72D1D2F6B458_zpswgu1x93o.jpg"/></a>

The two ends each go to a box. The middle in a one directional pressure pump. The four valves are synchronized A-A and B-B. With the A on and B off, flow is to the right. With the opposite, flow is to the left.

The transition will be wasteful since the connection loops around the pump will carry the flow. A DC pump could be synchronized to ramp down to zero so the switching can be performed without flow and without loss.

 

[karimwassef]

I don't know of any massive flow (20k gph) @ high pressure (20ft) reef capable DC pumps?

DC Pool pumps ?

Could also turn the AC pump off, but with continuous repetition, it would be short lived?

http://www.jandy.com/~/media/zodiac/global/downloads/sa/sa6220.pdf

 

[karimwassef]

Little more research on this... The loops can be condensed into two three way actuated valves like this

http://www.valworx.com/product/elec...rt-115v-240v?gclid=CIPMj6_umMcCFQYvaQod3f8J5g

<a href="http://s1062.photobucket.com/user/karimwassef/media/Mobile%20Uploads/7682D645-11F4-4970-A7BC-40B01BB62D20_zpsycypknrs.jpg.html" target="_blank"><img src="http://i1062.photobucket.com/albums/t496/karimwassef/Mobile%20Uploads/7682D645-11F4-4970-A7BC-40B01BB62D20_zpsycypknrs.jpg" border="0" alt=" photo 7682D645-11F4-4970-A7BC-40B01BB62D20_zpsycypknrs.jpg"/></a>

 

[Bent]

Here's an idea?

What would be wrong with using an air compressor and using it to force a volume of water from one spot to another?

You could even adjust the psi to the desired output, I can't imagine it taking much. Hook up an instant open solenoid and whamo.

 

[jake2045]

What about two pneumatic pistons on either end of the box timed to push down/up and reed valves to control the intake and outlet. The stroke would have to be 2/3 the tanks depth but while one side was pushing down the other side would be filling with the same volume of water being push out.

 

[karimwassef]

Bent- the air compressor could be a tad loud

That's kept me from considering pneumatic options. I guess the actuated piston we were talking about before could be pneumatic. I'm not sure how to set it up where the compressed air directly displaces water to create the motion.

 

[karimwassef]

Jake - the up/down motion of the boxes would push the water horizontally (sideways), but I think it would also create a wave that's vertical (up-down).

Here's what I expect would happen- So if you push a box down on one side, the water under the box has to get out of way. It will go up and sideways. Depending on the speed, a lot of it would go up against the plunging box and create a big wave that travels sideways. The one on the right would be creating a sink or a hole as you pull it up, that will pull the surface water down and to the right. The up-wave traveling to the right and the down-wave traveling to the left would meet in the middle. They would cancel and the net will be a shift of the water volume, but it wouldn't be laminar. It would come with a big wave.

Maybe that's ok depending on the rate of the plungers. But I think to move a lot of water sideways, you'll also move a lot of water up and down?

 

[karimwassef]

This brings up a good point that I think was part of the confusion in the beginning and Gorgok kind of explained it a bit.

When snorkeling, I'm floating at the water surface. The water does move in a wave, and this wave is moving me forward and backward a lot, but it's barely visible on the surface. It's not moving me up and down very much. The reason is the size of the wave and the 'tank' I'm in. The wave is 20 feet long but maybe 6 inches high over the water. Most of the wave is the 12 feet you can't see under the water. It also runs for a mile sideways....The point is that this wave is massive but barely visible because of how it is spread.

For a little snorkeler or coral, for the 10ft of space I'm swishing around in, I don't see or feel a wave. Locally, it's just a tiny little fraction of the real wave and it is very smooth and laminar. All other motions are spread so thin that you don't feel them. Only the forward-backward flow is felt and it is intense.

Why does it matter?

Watching the corals - it's as if they're breathing as they or their polyps are exposed to fresh water from opposing directions with a few seconds. It literally feels like a smooth, giant inhale-exhale with no turbulence or whipping around.

In a reef tank, with pumps, surges and powerheads, the scale would be a few mms of space where that's duplicated - instead of feet of flow. The only way to replicate the natural flow is to use a wave machine in a massive pool, or use an artificial means of creating laminar flow.

It's the same idea engineers use to mock up what a car would experience on the road in a tiny little test chamber. You create an artificial system to emulate the natural and real world.

 

[karimwassef]

Some bad news... Working through the laminar flow math (Reynold's number, hydraulic diameter, entrance length), I come up with these formulas and results
With
speed v=4in/s
slit opening t=1/8"
Re = 1389 v * t = 694 (this needs to be less than 2100, so good here)
Le = 167 * v * t2 = 10"

So for this to work, the slits can't be 1" deep, they need to be 10" deep!

Making the slits bigger makes it worse. At less than 1/8", the back pressure goes higher. Might be an option, but discounting it for now. Making a deeper slit (2", 3") would help but I don't know how to machine that...

So, a 1" deep slit at 1/8" thickness would only work at 0.4 in/s of flow... Over 5 seconds?", that's only 2" of water movement

 

[karimwassef]

Back to straws?

 

[karimwassef]

So... If I accept 1in/s flow, and accept an imperfect flow (not fully developed laminar flow), then the slits are marginal at 1.25" depth.

 

[karimwassef]

Redid the math for standard little coffee straws 5.25" long x 1/8" diameter. It works at double the flow even.

Speed v = 8in/s
Straw diameter d = 1/8"

Re = 694 v * d = 694 (ok)
Le = 41.6 v * d2 = 5in

So the 1/8" coffee straws at 5.25" would work at 8in/s of flow.
Keeping them in place becomes the problem. Mesh or netting before and after, maybe.

Mesh isn't rigid enough so I think I'd need to add eggcrate before and after..

Eggcrate
Mesh
Straws
Mesh
Eggcrate

 

[ericarenee]

This

I still think to get the steady back and forth motion without over complex mechanics and less surface wake this is the solution..

As it will push and pull the water gently back and forth depending on the speed of the motor..no water pumps The mechanical assembly on the motor to rods a gear assembly on the motor with a rod offset on a flywheel.... the water motion can be adjusted with a controller if you use a DC Motor...

Instead of the rods connecting at the ends of the tank they could be above and would need not need the extra room on each end of the tank....

 

[karimwassef]

I don't think the rods can go up since the top is sealed, right?

I think whether the drive is pump, motor-rid driven, pneumatic, actuated... The flow needs to be laminarized to avoid the energy going into a wave.

The in-tank piston only has linear action, so maybe it's the most efficient. The two sides don't actually have to be connected externally. The Pistons just need to be synchronized.

It does take up a lot of room though.

Length of the piston actuator (shaft/motor)+length of the piston chamber+linearizing box.
To move a 12" block, of water, it'll take 12+12+6 = 2.5' on each side. This probably works best with a pneumatic cylinder to move as hard and fast. To move more than a 12" block, the design needs to grow.

The pump approach is more wasteful, but much smaller I think. The space inside the tank is 6" + 2" for the plumbing ~ 8" on either side. But it needs a lot of external pipes and a massive pump like a Reeflo commercial 3HP Baldor. It also needs two three way valves and an actuator circuit. It is independent of the waterblock size though. So whether it's a 12" or 24" block of water, the pump can do either without more room. It's just a question of how long to keep the flow in that direction.

So - piston is probably most efficient and simplest, but the physical implementation requires more skill than I possess (giant hydraulic piston box) and is less flexible in making changes later.

The pump is not efficient, and requires more plumbing and circuit complexity (pipes, valves, actuators), but I know how to do that stuff. It should be more flexible to tune.

Both will need control circuitry, but I can do that part.

 

[karimwassef]

I think it's s combination of the best way to do it and what I can actually DIY

 

[ericarenee]

I think it's s combination of the best way to do it and what I can actually DIY

Got-Cha........ But i thought you could do anything....