Thanks for the numbers Ph. I think BalefireX may have gotten something mixed up. The interactive graph clearly ends at 1.85gpm, and not 1.71gpm. Actually in looking it over, it seems to be just the last segment between the last two plot points. Everything else looks okay. Everything up to 1.5gpm is okay.

Would it be possible for you to put a folder somewhere with these sorts of figures for each block tested? I'm very interested in doing performance vs power analysis for at least the top 8 to 10 blocks on the interactive charts (where I have pressure drop information available).

Not understand.
We were having a happy discusion(the odd dig) about Q*dP .
Why stop in it tracks.
A killed serious thread

That is what appears to have happened - don't drink and graph!

I've sent pH a new (and doublechecked) graph overlay

Well it seems to be the time for people finding computational errors. I found one myself, and have re-plotted the graph. I'll add some more blocks as I go. Fairly confident this is correct now. Decided to remove the logarithmic axis. Although interesting, it places a lot of visual impact on the hydrarulic pumping powers that simply don't commonly exist (ie. <0.5W).

Edit: Graph deleted due to errors with best-fit smoothing algorithm

(sigh - I'll get it right one day)

I don't know what to say Les; I can't control what another website does. It wasn't specifically caused by this post though; it was I think in retaliation to the other thread about "what happened to the Nexxos XP review"

That's really neat Cathar. I am still trying to decide whether it's better or worse to try and explain hydraulic power to "avg Joe". Seems reasonable though. The G4 graph on the Pro/Testing page is fixed now; sorry for the error

it was my understanding that C/W per dP graphs were derived from dP per flowrate data

i dunno, just thinking of billa's work

pHaestus,
I apologize ,I was/am wrong.
I should keep out of the kitchen and stick to numbers.

No probs here Ph, it seems to me that only you and Jaydee got redirected :D
(j/k of course)

Raises a smile.
Beermats still soggy here.

I believe I've finally gotten all the bugs worked out of the procedure.

Even if nobody else really believes in this, I am gaining increasing confidence in it. The following graph's patterns mimics near exactly what I see/saw in my own testing with fixed power input fed to the pumps. There would naturally be some variations though between pump input power and hydraulic power depending on where one sits on the efficiency curve of the pump setup, so the correlation is not going to be perfect. I believe that this is the corrections that Since87 was trying to solve with his posts at OC.com.

In my own testing I'm using hydraulic powers from around 1W to 8W being fed to the blocks, although I guess that I really tended to focus on the 1.5-3W range when I look back at the work I've done and correlate it to hydraulic power.

Anyway, here's the updated graph that does contain some extrapolations to arrive at the 4W power figure.

http://www.employees.org/~slf/curves...r/perfpwr3.png

[Edit: New graph - more blocks]

Nice! Hardly surprised to see the G5 is miles ahead ;)

I certainly believe these graphs are much more meaningful than just C/W vs flow.
Flow is always only half the story...Your graphs give a true indication of waterblock efficiency (or is that efficacity?)

Looking back at Since87s' post, as I understand it, the purpose was for the tester to measure the blocks performance at one point - corresponding to a typical system flow rate. Maybe I misread it though...

BTW, I am now very curious as to how the "old-school" blocks would fair with this rating system?

Fits sweetly with any of the old C/W v h plots
eg Fantasy
WW3

Possibly indicating the importance of your attention to non-contributory power in the G series.

I'm going to quote this from the NexXxos XP thread to make sure the info doesn't get missed/lost and keep this discussion in one thread:

Thx pHaestus!

This is less relevant, but I'll include it as a logical conclusion.

http://img33.exs.cx/img33/6618/nexxus-mcw6000-pumps.gif

edit: and this one with added pump heat:

http://img34.exs.cx/img34/5439/nexxus-mcw6000-temps.gif

15W for the MCP650 sounds a little high(?)

You guys are too damn clever. Now I suppose all that you need is pressure drop numbers for all the wbs I've tested right?

You must be telepathic :)

If I was clever (or had a conscience...) I would have written a scipt in Matlab or better still created my own app in Perl ;)
As it is, it feels like I've gone the long way around to produce the last graph - bit of a half-assed way of doing things really. But hey, I may just have learned something on the way :D

Probably the other big thing to do is for me to put together a test loop that contains 2m 1/2" ID tubing, a thermochill 120.2 and the papst fans at 12v, and the blocks/pumps we are modeling. Use it to cool the test system I collected all the data on and we can see how closely the theory matches up with actual performance. Rather unexciting (the results SHOULD match up) but necessary I think. Can I find this radiator and fans in north america?

Not sure about the fans, but I suppose and fan with the same specs should do, the rad can be had at DD: http://dangerden.com/mall/Radiators/thermochill.asp

I don't see any of their canadian distributors stocking the thermochills. I guess I'll need to order direct from DD.

You asked about North America? AFAIK, DD has an exclusive at least in the US on the Thermochill's. www.mountainmods.com has them too I believe (via DD). Ben Rising over at Mountain Mods is a very good guy.

I was looking at the DD resellers in canada for someone who might carry the thermochills. Figured I'd save on customs fees and shipping costs that way.

Joe just PMed me from IRC that the madshrimps people (jmke and liquid3d) have been banned from the forums and their IPs are banned from even viewing this site. I apologize for the interruption in this discussion earlier. Hopefully it won't happen again.

(from Nexxos thread regarding PQ) Re the P=Q^1.85 fit, I think there is a better way.

I assume you are familiar with the idea of a "k-factor", I stumbled across it recently when exploring the flow measurement problem.
Your PQ curves are not behaving, shouldn't one be able to generate a constant which, even allowing for transitions between flow regimes and boundary conditions, is relatively flat across flowrate?. I am getting this with measured data, (see attachment) it is constant enough that I would propose that every block has a "K-factor", a constant encompassing restrictivity described by the equation: K=Q/sqrt(dP) or P=(Q/K)^2, essentially the flow rate squared relationship. It's probably your curve fit that I am seeing, it is not generating a constant. If it is real, that's very interesting, there's probably a way to extract a Reynolds number curve from it.

Sorry if I am being disruptive, I have not been following this closely but I thought the K-factor thing might be relevant. It for sure is another way to generate a PQ curve from a single data point...

:)

yes, you are correct
I am in the process of converting all Swiftech flow resistance curves to a 'K-factor'

pH or Cathar
why not write an article on flow resistance characterization ? (yes, I'm lazy)

Bill I have a question about dP measurement. It seems to me that the easiest way to deal with all the different possibilities of tubing and fittings and such is to:

1) zero the xmitter
2) Run a length of the tubing to be used over the flow range of interest (blank)
3) Cut the tubing in half, mount block/rad, and repeat (sample)
4) sample - blank = dP of only block/rad (this takes care of the dP of crosses and fittings and tubing and all leaving only wb).

Is that unnecessarily complicated? I was concerned that the friction factor of clearflex or silicone would be difft enough from copper pipe to make doing a calibration with just copper pipes of difft ID to be a mistake.

Hmmm, maybe some of you more engineering types could help me out to understand as I may have the following wrong (being self-educated and all on this stuff):

P=(Q/K)^2

seems to me to be simplification of Bernoulli's equation. However if we consider viscous head, being the energy that gets lost as heat (and absorbed into the liquid itself), then for turbulent flow the friction co-efficient of the viscous head term will fall away as the Reynold's number increases (which is proportional to the flow rate).

So what we then have is an effect where P=(Q/K)^2 isn't really followed cleanly. For the more restrictive blocks I intuitively would have thought that they would deviate even further from the classic P=(Q/K)^2 equation.

Now, quite true, Bernoulli's viscous equation consists of two primary terms, being the constant head loss due to inviscid flow (which is proportional to the flow rate squared), and the head loss due to viscous flow. The relative effect of viscous flow term diminishes as the flow rate increases, meaning that we end up with a curve that doesn't fit P=(Q/K)^2 any more.

I threw out P = Q ^ 1.85 as a really quick and dirty approximation of this effect, perhaps only valid for within 0.5 to 2.0x the data point given at somewhere like OC.com.

I measured various data points from 2.0 - 5.0LPM for the Storm/G4, and it didn't seem to me to quite follow a simple P=(Q/K)^2 curve.

That could also just be due to measurement error too.

Or perhaps one of you kind lads could tell me if viscous flow effects don't even apply here?

nothing is too simple once one gets into it

- the dP units are temp sensitive, if not temp controlled you'll need a zero reading at the start and end; use this to 'correct' the dP reading
(I would not suggest re-setting the zero, this is part of the unit's cal)

yes, your procedure is correct
I lay out the crosses flat on a table and connect them with a short piece of tubing, run a dP curve, then cut that tubing in half to connect wbs; then the single connection loss can be deducted from the wb reading at each flow rate

but you need to do this for each tubing size you will be testing with

What about the fact that the tubing has a curve in it when the wb is connected, but is straight through w/o the block?

Isn't that the same law used by the Hazen William equation?