To see if my fumbling theory holds true in practise.

So, we will see some fumbling numbers eventually.
Excellent, look forward to playing with them.

If you're asking for a graph of the relationship between viscosity and performance drop, I don't have one.

With water, the turbulence enhancement appears to offer around a 20% improvement in h over the closest equivalent mathematical model. That 20% is mostly emperically determined.

I roughly predict that the 5x more viscous liquid would roughly reduce that gain over the standard model to around 5-8% above what the standard model would predict for h for that level of viscosity.

Again, not plotted. Am more interested in emperical evidence and formulating rough theory, than attempting to assume that I have a hard theory that works.

Or this is an interpretation of pH's results?

Why not just add 25% glycol to your system and see if the theory holds true. Are you measuring your temps through the socket or the internal cpu sensor?

Edit: I just realized you don't have the block back yet

What comes first? The results or the theory?

Am aware of the impact of viscosity. Am unsure of the scale of the impact. Have some thoughts. An uncorrelated data set of 1 (Phaestus's results) is hardly something to form a theory around (unless it involves sticking one's hand in fire). Guesswork at this level Les.

Thanks for the update Cathar. Some interesting developments.

The gains of the G5 vs other blocks will be of great interest.

Thanks for sharing what you can at this time. :D

I think almost totally reponsible Les

From properties here.

Some charts:
Density and Viscosity
http://w1.863.telia.com/~u86303493/C...rt_VD_vs_T.jpg

Giving Kinematic Viscosity
http://w1.863.telia.com/~u86303493/C...rt_KV_vs_T.jpg
Well, some fumbling.
http://w1.863.telia.com/~u86303493/C...Re_vs_T_kv.jpg

(how do you push 4 lpm through a 2mm diameter tube?)

The step from Reynolds number to Nusselt to "h" is fraught. I have no idea of the barrier thickness, no clue how to guess either. Empericality rules. Suffice to say that Nusselt (and thereby "h") is proportional to Reynolds. Ish.

Think it boils down to the "Ish"
From here, one of my fumbles with "ish"'
Now think "h"s are too high(over estimate of C/W(TIM)) but .....

Some interesting/useful data plotted, will digest.

[quote=Les]Think it boils down to the "Ish"
Earlier in this thread(page 4) one of my fumbles with "ish"'
Now think "h"s are too high(over estimate of C/W(TIM)) but .....

[quote]

Unsure of the exact numbers but your curves look like what I'm getting Les. Will check specifics later.

Here are some Nusselt curves,
http://w1.863.telia.com/~u86303493/C...t_Nu_vs_kv.jpg
more proportional to "h" than Re.# is.

Predicted effects of changes in Kinematic Viscosity on h(conv coeff) at constant Density, Conductivity and Heat Capacity.

http://www.jr001b4751.pwp.blueyonder.co.uk/Cascade2.jpg

What you've plotted is the basic variation in convectional efficiency with viscosity. What I'm having troubles with solving is what's occuring within the G* blocks before the convectional action. Increased viscosity will definitely be interfering with the longevity of the "turbulation" effects that assist with the block's increased convectional activity.

Have completed re-drawn plans for the G4/G5 which should improve things slightly, and should not be at the expense of "plain water" performance.

Still, it is rather an interesting relationship, and definitely something for people to consider before dumping heaps of glycol in their cooling loops.

Suggest "longevity" is included in the Impingement(Flomerics) calculations.
The Velocities(4.17m/s and 6.67m/s) are those in the nozzle.

Would suggest that Flomerics is attempting to model "classical" jet impingement only.

Yes, it is, also, my understanding is that it is not intended for Submerged Jet Impingement(SJI).
Probably a "fumble to far" to suggest any major "longevity" contribution.
Will wait for your model, when wb's details are released, before further sums.

I think it suffices well enough for SJI, at least in a relative sense. It seems to roughly agree with my experiences, with performance differences for varying jet standoff heights being the notable exceptions.

So yeah, acceptable as a good guidleline for initial starting points.

If C/W(TIM) ~ 0.1: yes.
However if C/W(TIM)~ 0.05 , I think I prefer Sieder-Tate( eg Re(3x1mm Entry) from here )
Graphs are still being developed.

Edit: Typo: "C/W(TIM)~0.05" did read "C/W~0.05"

I am unsure if this contributes anything to your divagations....
I refer to Incoherent's graph showing relationship between Re and kinematic viscosity. Isn't there an equilibrium between kin. visc. and Re number? If kin visc. decreases then velocity increases and hence Re goes up as well.
Just some idle thinking here, if worthless just ignore and do not reply :)

Yes it would. I'm not quite sure what you mean by equalibrium in this case though. More a strengthening I'd say. Or?

Also something for the testers/reviewers out there to consider as well. A block could possibly show massivelly improved (CPU-H2O delta T) performance simply by increasing the water temperature.
I'd love to see if there really is a difference. All very well to play with numbers but it's nice to see real life.
(I discovered something else today. Hot water can freeze faster than cold water. An old wives tale that is actually true but not understood.)

well I was waiting to see if the obvious would be discussed
sure the viscosity changes, and with good instrumentation AND good technique the changed performance is readily apparent
- this suggests an 'optimum' temp (IF the wb has been so designed)

tweek away, are the blind fumbling for the light switch which is not even connected ?

sorry guys, these are numbers for the sake of numbers

I'm just waiting for my blocks to get back to me...

Well, numbers are interesting, and are quite illuminating themselves. The temperature/viscosity relationship is moot however, since our end goal is (normally) lowest load temperature, not highest convectional efficiency. I think 'optimum' coolant temperature within the bounds of reality is as cold as possible.
The viscosity in itself however, is highly relevant.

Not "numbers for the sake of numbers".
Numbers were used in the design:
Playing with a performance number(h(con coeff)) and kinematic viscosity

I think I understand what is being played with,
but when the desired/reasonable result is arrived at via fiddling with the factor of interest; . . . . .

ignore my skepticism, it is not new news on this topic - (h