Thoughts on water pressure & flow rate...

[Since87]

Originally posted by Les
Also had me worried.
Like yourself I do not like posting misinformation or wrong calculations.
However all looks sweet.

I'm busy posting corrections where I can think of. If I'd paid closer attention to your graphs in that O/C thread, (Or Graystar's last post in that thread, which I seem to have missed completely.) I might have realized my mistake much sooner.

My radiator spreadsheet has the same problem, and is utter crap.

It'll take about a minute to correct the equations, and then an hour of 'trial and erroring' the fudge factors to get it 'right'. (I hope.) It's not going to happen tonight though.

[Since87]

Nope, you were right Les. There is another problems with my graph.

Apparently when I'd originally done it, I pasted in the 'flow resistance' for a Lytron 6320 radiator instead of White Water.

It's been a long day.

Will fix later.

Edit: My correction post has been corrected.

[MadDogMe]

If your pump were to fail then the time would be dependent on the thermal mass of the WB and the water inside it

I had a pump fail (fail to be plugged in ) and everything was fine because my rad was higher than my block and 'natural' convection took over. It leveled out at 45degC, only about 8degC higher than with the pump!...

What I'm saying is there's more to be factored in than just the mass of the block. Pump redundancy isn't needed if a little forward thinking is exercised...

[Blackeagle]

Les,

Love your graph work man, very helpful to me in grasping some of the posted info.

Could I ask you one favor? Could you include the curve for the smaller Iwaki MD15 & MD 20z pumps?

[Les]

Originally posted by Blackeagle
Les,
...
Could I ask you one favor? Could you include the curve for the smaller Iwaki MD15 & MD 20z pumps?

All posted graphs are ,unless labelled otherwise,
for 50MHz flavours.
Although would expect different PQ curves for all pumps at 60MHz only Iwaki show two sets of curves.
Eheim being a European manufacturer I used 50Mhz data as possibly the more representative.

If can find original Excels will eyeball some 60MHz pump curves.and post in this thread.

[Blackeagle]

Thanks Les,

For comparison of one pump vs others 50hz would be fine.

60hz is however a better test of what I can expect when I get a system running.

Thanks again!

[Les]

Originally posted by Les
.........
If can find original Excels will eyeball some 60MHz pump curves.and post in this thread.

Added Iwaki MD-15R(M)-N 60MHz and Iwaki MD-20RZ(M)-N 60MHz to second graph which now includes a Swiftech wb.

[LPorc]

Originally Posted by MMZ_TimeLord

I think I'll stir this up a bit with this question...

If one pump and one loop (basically) in your systems works okay... what if you put TWO loops and join them at a reservior with two different pumps one for the radiator loop and one for the cooling loop (CPU block, GPU block, HD block, etc.)?

Would a differential in flow rates of the two loops to compensate for the different surface areas in each set of thermal transfer devices increase performance?

I read through the rest of this thread and saw no response to this question. I am curious, too. I am new here and have been lurking, absorbing and filtering knowledge and twiddling with some design ideas for my first WC rig. I ended up here because there are fewer obviously wrong thinkers here. Y'all at least have the grace to keep your wrong thoughts more subtle than some of the other sites and forums I am not the sort to jump into the pool halfway, so I plan on lots of flow restricting components as I go overboard with a fully WC setup, and over-engineered at that ! I like to get my ducks in a row before lots of time, money, and materials are expended, and do my best to ensure a satisfactory result. I've learned a lot lurking here, but I've got more to learn before work begins in earnest. Pardon my n00bishness :shrug: .

I've seen MMZ_Timelord in another thread talking about pushing pumps into a resevoir with a common outlet. I don't think pushing disimilar head pumps into a tank will work, there's the matter of backpressure to consider. If the pumps weren't exactly matched, wouldn't the smaller head one be fighting against the load of the difference and actually backflow if the rest of the circuit past the push tank was more restrictive than what its remaining capacity could handle? In other words, the system could not be more head restrictive than what the lower rated pump could push, and the lower head pump would be under greater load. At least that's my n00b guess.

I've had a similar thought, though, except rather than pushing multiple pumps into a tank, I envision feeding multiple pumps from a common resevoir. The resevoir will be tall, and the feeds staggered low so that gravity and some baffling will minimize pump competition on the suck end as well as promote turbulance for the inputs to the resevoir (both for air and heat exchange, see below). I was figuring on two pumps, but now I am wondering about three...

What would the effect be of having a separate radiator circuit fed from a common resevoir as other circuits? A pump running just the radiators should get a better flow rate through them than in series with other head-robbing components, and the other circuits a better flow rate without radiators (or with less restrictive radiators, did I mention I like to over-engineer?). Would this improvement be enough to cancel out the loss from the coolant-to-coolant free exchange in the resevoir?

Will the fact that we are in a closed system negate my attempt to limit pump competition on the suck end of the feed? Or would this actually be a good thing as the combined draw of the pumps would be helping the more flow restricted inputs? Or would it make them worse by helping the less flow restricted inputs more and cause me to have to tune the inputs to satisfy my anal nature? Or am I in the same problem area that I perceive the push tank to be in because all I am doing is moving the point of push to the other side of the circuit (although I do have 3 ins and 3 outs)?

Well, I think that's enough n00b musings and questions for now. Am I thinking clearly, or am I just another clueless n00b ? Give it to me straight.

[MMZ_TimeLord]

LPorc,

I was indeed trying to say that two pumps would utilize the same reservior to DRAW water from and pump it throughout the system and then return to the reservior.

I will not be doing this on my current system as space limitations would not allow it.

The idea of a separate pump for just the radiators and one for the CPU/GPU/HDD/NB, etc. is interesting. I would like to know if that would allow better removal of the heat since the radiator would have MUCH higher flow with that setup. :shrug:

[LPorc]

Originally Posted by MMZ_TimeLord

...
I was indeed trying to say that two pumps would utilize the same reservior to DRAW water from and pump it throughout the system and then return to the reservior.

I will not be doing this on my current system as space limitations would not allow it. ...

Ah, I must have misunderstood, or perhaps confused someone's reply.

I have the advantage in that I'm starting from scratch with my over-engineering, so once I figure out what all I want in the box, I'll build a box to hold it

[lolito_fr]

The idea of using different flow rates for radiator and cooling loop was discussed on OCAU. You might need some aspirine though

[LPorc]

Originally Posted by lolito_fr

The idea of using different flow rates for radiator and cooling loop was discussed on OCAU. You might need some aspirine though

Thanks! I activated over there and read the thread. The numbers were pretty straight-forward, although for such a short thread it did meander a bit.

The bottom line I got out of it is that in theory we could get a small gain, but the gain is small enough we might not get it in practice. From my point of view, more importantly, is in theory we don't get a loss. The plumbing might be a little more complicated, but it does give us some options, and can let us use disimilar pumps effectively.

Speaking of pumps, anyone here build their own or investigated other types of continuous flow pumps?

[lolito_fr]

Yes, I think the main advantage to your idea is flexibility rather than extra performance, as you gain more from increasing flow through the blocks than through the rads.

Re pumps, I have successfully "converted" a 180w draining pump (83lpm/5.5m) into a 3-stage unit capable of approx 45lpm/11m. For watercooling, but not PC
Its dead now, but I still have it lying around somewhere...

[liaisonextreme]

I just read this whole thread and I learned a hell of a lot, now I need to go eat some tylenols and take a nap. You guys are crazy.

[bigben2k]

Originally Posted by liaisonextreme

I just read this whole thread and I learned a hell of a lot, now I need to go eat some tylenols and take a nap. You guys are crazy.

Welcome to the club

[G33k]

Going back to the bits about pumps failing, back in the good old days when I ran an Original (Slot-A!) 750Mhz Athlon (running at a whopping 963Mhz ), I had a too had a pump failure (also unplugged lol). This is what I found when I plugged in my temp-monitoring software :



Bear in mind that I'd left the machine on for about an hour or so, so I'd guess the temps were about stable. It was amazing how soft the tubing went when I turned the pump on, but fortunately, no leaks / breakages!!

P.s - Amazing thread btw - I've not being paying much attention to w/c'ing recently as my degree (read resits ) took priority. I'm starting to get back into it now and this thread was an amazing recap / learning experience. Well done to all - now if we could just condense it into a singl page, I'd say you have the beginnings of a WC'ing bible!

[Pureh20]

generally when were talking pumps max head is more important i watercooling loops and the reason is because of the restrictive design of cpu blocks, Nb blocks gpu blocks etc.

an example of this is comparing the swiftech mcp600 pump (690lph, max head 3.2m) to the eheim 1250 (1200lph, 2.0m max head) the eheim is designed for aquariums and ponds hence its more of a free flowing pump and has an open impeller, the swiftech has a closed impeller and produces higher head, this is beneficial because when we get into restrictive setups especially with blocks like the cascade and white water. the pumps with higher head will have a higher flow rate.

well thats my 2c, back to biology practical :s

[Myth]

Hi all

What a great thread! I live in Denmark, and the ppl. over here tend to go with the theory that flow doesn't matter so this was indeed interesting to read!

Does anyone know (or care to do) a real life test using the same system and different pumps to show what the "real world" gain of better head/flow is? since it can be a bit difficult to piece it together from the different "lab" results..

[*klonk*]

Originally Posted by Myth

Hi all

What a great thread! I live in Denmark, and the ppl. over here tend to go with the theory that flow doesn't matter so this was indeed interesting to read!

Does anyone know (or care to do) a real life test using the same system and different pumps to show what the "real world" gain of better head/flow is? since it can be a bit difficult to piece it together from the different "lab" results..

Are you thinking *cough*-deleted-*cough* ? yeah im from DK too and ppl really insist that flow is secondary - and great thread - i read it awhile ago and theres alot of good info here

[threeputt]

Wow....I suddenly got the urge to go back to school and register for thermodynamics and fluids class...