whirlpool effect in res

[Talik]

So, I'm gonna use, for my resevoir a clear plastic pipe that runs outside my case
_________...__
|.case.......|..|..| r
|........-->.=|=|..| e
|...............|..|..| s
|...............|..|..|
|...............|..|..|
|........<--.=|=|_|
|_________|

kinda like that.here for better sketches of plan and tube. (I'm not on my computer, so I can't do anything pretty.)
The pipe will probably be about 12"-18" long and 1.5"-2" in diameter. Flow will be in a downward direction with a 1" tube coming off of the bottom going directly to the pump. The top will be fed with a 3/4" tube coming from the waterblock.

My question is weather it is better to, at the inlet, have the tube be offcenter so that the water swirls and creates less turbulance from hitting the back of the pipe, or to have it just go in centered.

(top view of pipe with tubes coming in)

this
.........._______
____ /..............\
.......| -->...........|
____| -->...........|
........\________/

or
____________
......../ -->........\
____| -->..........|
.......|...............|
........\_______/


The hope is to, with the whirlpoop effect, create less turbulance to break the surface of the water and bring air bubbles into the system. And maybe look a little cool, too.

-Talik
[EDIT] changed spaces to periods to avoid html ignoring multiple spaces in pictures.[/EDIT]

[zoson]

Just an FYI air in lines = bad.
-Zoson

[myv65]

From a purely functional standpoint, don't bother with a dedicated reservoir. Your system would be every bit as effective (and smaller) if you merely used the same tubing for your "reservoir" as you have inside the case. I suspect you want the reservoir larger for a few reasons including:

1) Air trap
2) Fill/drain/bleed location
3) "Looks"
4) Perceived benefit to cooling

You don't need #1 if your system is sealed well and you have a point for bleeding air. You can do the first parts of #2 with a T in the line. Number 3 is completely your call. Number 4 is not applicable as a reservoir does essentially nothing for cooling.

All that said, if you wish to have the reservoir as you've described then it should not be too hard to eliminate air bubbles. Air bubbles have a tendency to rise to the top at a predictable rate. This rate is on the order of 3 feet per second (going from memory here, but should be close). So long as your reservoir runs nearly full and your downward velocity is low enough, the bubbles should not reach the pump intake. A 2" diameter will keep the velocity low enough so long as you don't "drop" the water too far at the top. The other option is to place a baffle in the tube. This is nothing more than a roadblock to break-up a flow stream that is not uniformly distributed. A stainless steel screen does nicely.

If your aesthetics allow, a submerged return would be even better at preventing air entrainment. All depends on what "look" you're trying to achieve.

[Talik]

yes.. air is bad
my reasons for having the resevoir are as follows:
1. easy to fill the system. easy to cap.
2. removes air bubbles, I have a very (over)powerfull pump and high flow system, and I fear that the turbulance in a regular air trap would put bubbles into the system, as well as slow the flow.
3. allow for the pressure of the pump to equalize somewhere.
4. get the watter back down to the pump.

3 feet per second, eh? anyone know how fast my pump might push water through my 2" res? (I know someone's gonna tell me my pump is too big, and I know, but it's what I have for the time being)

the following image shows more accurately how this resevoir would fit together:

[myv65]

If you can get the flow to spread out in that 2" reservoir, no worries. Even if you have 1/2" as the minimum ID in your system, a 2" ID provides 8 times the flow area. This means if you're going 3 FPS in the reservoir, you'd be doing 24 FPS somewhere else in the system. This is typically beyond the ability of even "strong" pond pumps. The trick is that flow is not truly uniform across a cross section, hence the recommendation for a screen or similar to break up and distribute the flow in the reservoir.