A TIM C/W number.

[Incoherent]

Originally Posted by Les

Assuming a simplified picture of uniform TIM layer and no contact resistance(TIM/Cu).
The usual picture is of TIM filling voids and then including Cu/Cu and TIM/Cu contact resistance
Have no authoritative links to hand (long time since looked at - put on hold - a can of worms)

Yes interferometry and load cell data would be useful but wouldn't expect a simple interpretation.

God, am struggling with the sheer volume produced so far in the Excels.
Converting to beermat format is a challenge.

I agree about it being a can of worms, I was being tongue in cheek with regards to TIM thickness.
Load cells. Hmm you've given me an idea for measuring contact pressure. Does anyone have any links/sources for load cells, pressure sensors?

The data volume does get pretty heavy alright. For even more data I can actually sample at 1ms, as I have just tested, although I am concerned about the loading of the channels at this high rate. CPU load goes to 100%, logfiles assume massive proportions very quickly and we get saturated. But, it lets me perform some meaningful Fourier analysis in the search for mains hum and other periodic interference.

[Les]

Originally Posted by Incoherent

I agree about it being a can of worms, I was being tongue in cheek with regards to TIM thickness.

Yes, did notice the smile.
Thought would post before others got carried away.

Slowly accustoming myself to the Excels
However, even now, I realize your manipulation techniques are beyond mine; but will plod on.

On a more mundane point , yes, Kcopper=393 is probably a little high, dunno about Cp(water)

[Les]

Had a play, nowhere near as rigorous as your analysis
It is fascinating stuff
Have taken a random snapshot of 100 data sets(out of several thousand) from the calibrated log2 .
My manipulation skills not up to dealing with all at one sitting.
Averages :



Gives:
Power in (145.226601/R) Watts (cf 72.61W} (V^2/R) not found a value. for R
Heat Flux 72.098 Watts (cf 72.26W) (k*A*DT/L) k=293
Heat to Water 70.090 Watts (cf 70.256W) ( (FR*Cp*(Tin-Tout)) At a flow rate of 3.22lpm and 4186 heat capacity)

C/W values (140 sq mm die)
TIM : 0.0356 C/W (cf 0.0359 C/W)
WB : 0.0973 C/W
WB+TIM : 0.1329 C/W
WB+TIM+Offset : 0.1581 C/W (1.4mm Offset)

The (WB+TIM+Offset) C/W is usually quoted(e.g JoeC) as the C/W for the waterblock.
It would be fascinating to compare results with JoeC's(140 sq mm die)
Do you have any of the wbs he tested ?
Most preferred would be one also tested by Billa (on a 100sqmm die) and pHaestus(on a cpu).
Sorry, I am dreaming up work for you whilst I go to the pub.

[Incoherent]

Originally Posted by Les

It would be fascinating to compare results with JoeC's(140 sq mm die)
Do you have any of the wbs he tested ?
Most preferred would be one also tested by Billa (on a 100sqmm die) and pHaestus(on a cpu).

I don't have any commercial waterblocks, have always preferred to make my own of everything where possible, for both financial and personal reasons. At the moment I can't justify the cost of buyng one just to test it.

But you are quite right, a direct comparison is definitely necessary, an MCW6002 is probably a good choice so when the setup is a bit more verified I'll start saving pennies for that.

Originally Posted by Les

The (WB+TIM+Offset) C/W is usually quoted(e.g JoeC) as the C/W for the waterblock.

I would like to know the details of the Offset for JoeCs setup. I don't frequent OC very much so I have certainly missed that somewhere. Sensor location and dimensions primarily.

[BillA]

I'll send a 6000 with the grease, what mounting system ?

[Incoherent]

Originally Posted by unregistered

I'll send a 6000 with the grease, what mounting system ?

That would be fantastic Bill.
Right now I am using the standard Socket A mounting holes (66.09mm x 36.14mm spacing) but I can rig for any type with a bit of work. Socket A preferred though.

Thanks for the kind offer.

[pHaestus]

I need to get your wb back to you as well. I am going to just post the review using the numbers I collected prior to leaks. I'll put a wb or two in the package when I return it.

[BillA]

nothing is ever easy
the only socket A we can accomodiate is using the 3 lugs, not preferred for this kind of work
- the wb is too big for the AMD hole spacing
I'll send the P4 setup which has holes for Nicona, also the 775 plate
should go out today as engn samples, $5.00 value

[Incoherent]

Originally Posted by pHaestus

I need to get your wb back to you as well. I am going to just post the review using the numbers I collected prior to leaks. I'll put a wb or two in the package when I return it.

Oops. What am I getting into here?

That'd be really good pHaestus. The more the merrier. I'll be happy to get the block back so I can see what went wrong, whether it's another case of polycarbonate heat cycle leaking or just my crap workmanship.

[pHaestus]

I would suggest making an adapter plate similar to the one Cathar uses for the Storm. Instead of using it to adapt your wb to the socket holes, though, you could use it to adapt the hole spacing of yout die sim to accept anything that mounts with 4 holes. If you make it w/ tapped threads for your posts then it should be pretty easy to use and quite flexible

[Incoherent]

Originally Posted by pHaestus

I would suggest making an adapter plate similar to the one Cathar uses for the Storm. Instead of using it to adapt your wb to the socket holes, though, you could use it to adapt the hole spacing of yout die sim to accept anything that mounts with 4 holes. If you make it w/ tapped threads for your posts then it should be pretty easy to use and quite flexible

I kind of am going to do that, but upside down. The Lexan base of the die-sim is the adaptor plate, I just need to drill and tap the spacing required and move the posts to whichever suits the block I am testing. In the future I will mount the posts into upside down through-hole load cells to measure mounting pressure. Thats for the far future yet though. I need to source some cheap miniature through-hole button cells. What I have seen so far makes me cringe price-wise but drool at the same time.
Until then the mounting pressure is a bit of a concern. I have found that it is possible to "tune" a given mount dynamically by monitoring temperature and adjusting the tension of each mounting spring. This is great for getting a given mount "good" but means the overall tension between mounts can be different. Bothers me.

Right now I am in setting up the unit in a mounting frame. A bit of carpentry which will enable me to maintain a bit of control over the mess of cables and hoses. I think it is important to get to a stable state which should not change under any but the most dire circumstances i.e. component failure, before I start any serious testing.

Checked the DAQ with a PS seperate from the heater yesterday, a "jump" in the temp readings I was seeing when plugging in the heater disappeared completely. So thats a relief, I was a bit concerned about that.

[Incoherent]

I have been doing a bit of concept proofing. By rearranging the WB water delta T power calculation one can generate a flowrate number. FR=(W/(Cp*dT))*60 from the water in/out temperatures.
I tested this using a bucket and stopwatch. The error using the heatflux number was up to about 3.5%, less at higher flowrates but noisier, caused probably by the fact that the waterblock itself is not insulated so the power to water is less than that through the fluxblock.
I think that I will use this. The Swissflow flowmeter I have is very inaccurate, understating the flow rate by over 12% and is very restrictive. I am moving to 1/2" fittings and this particular one I have is 3/8" OD barbs. Using the temperature to calculate it is very convenient, I am logging temps and can generate a flowrate (along with an instantaneous C/W, W, TIM dT etc)) directly to the log. It has a slow response but that can be decreased by reducing the metal mass of the water sensors.
So this gives me my very first C/W vs Flowrate curve. C/W values have been adjusted by measured TIM and Cu values to give the extrapolated WB base value.

Note that during the transitions between flowrates the curve does a little loop up or down. This is the delay effect of the water Temp sensors. Overcome with a moving average. The data file with calcs is also attached for those interested.
Edit: Note also this is only one mount. Preliminary but indicative data. Numbers will change slightly when I have finalised parameters.
Edit2: Added a filtered chart

[BillA]

urgently needed is a known reference
when I get back to the office I'll back calculate some datasets and see where I land
given your apparent good repeatability, any methodology can be made to work once understood
again, nice work

[Incoherent]

Been a bit busy recently, struggling to balance work, family and hobby.

Finally got the PWM water temperature regulation running. It is working very well:



This is a chart of the water temperatures (WB in and out) reaching the set point, wobbling a bit and then stabilising.

I am easily able to maintain a set temperature within +/- 0.01°C once it settles:



I think this clearly shows the advantages of doing things in the analog domain when your resolution is limited to 12 bits.
If only I could be certain my absolute accuracy was that good

Thanks for your insistance on the PWM Groth.

My main limitation now is the pumps. I am only able to achieve about 1gpm with what I have right now, with the Sphere block. This is not too much of a problem for things like thermal compound testing but restricts ones perspective somewhat with some waterblocks.

I am working on a solution for the mounting pressure issue. Hopefully I'll have a method soon. Then to start testing some greases.

[BillA]

jeez, I'd have bet the moon that such could not be done with PWM and a rad
- new lesson every day

how about with different heat loads ?

[Incoherent]

Originally Posted by unregistered

jeez, I'd have bet the moon that such could not be done with PWM and a rad
- new lesson every day

how about with different heat loads ?

I haven't tested it with varying heat loads yet, I would imagine that would trigger an instability or small oscillation. It is a matter of tuning the circuit to minimise this.
It is unfortunate, the PWM is tunable in the sense that I can adjust the sensitivity of the response by adjusting the modulating triangle waves amplitude, but this also changes the frequency - the most stable setting is also the most irritating tone.
The good regulation surprises me too, I designed the circuit to be in principle accurate but it is always a bonus when it works better than expected.

[lolito_fr]

Nice work!
(Is it me or is that top graph reversed? )
Would be nice to see fan speed/duty cycle on the same plot

[Incoherent]

Originally Posted by lolito_fr

Nice work!
(Is it me or is that top graph reversed? )
Would be nice to see fan speed/duty cycle on the same plot

The graphs are reversed actually, the time axis is scrolling from left to right, the right side, with the higher number, is further into the past. A quirk of the program.

I have been trying to come up with a way to incorporate a tachometer/frequency counter into this DAQ, a clean solution is eluding me at this point. So sorry, no fan speed readings. (and no flowmeter readings, but I am trusting the delta T flow rate calculation more and more). Duty cycle, I cannot sample better than 1ms, the PWM frequency is above this, some component value changes might fix this if I find it necessary.

[Les]

Originally Posted by Incoherent

....
My main limitation now is the pumps. I am only able to achieve about 1gpm with what I have right now, with the Sphere block. This is not too much of a problem for things like thermal compound testing but restricts ones perspective somewhat with some waterblocks.........

Yes, think you need a new pump for wb testing
Have you got PayPal account - will happily donate 35 GBP (or 456 SEK ) towards a purchase.
Let me know, please.

Hoping may produce result something like this :-



The MCW 6000 prediction is an extension of this discussion and is 0(TIM) and 0(offset).

[Incoherent]

Originally Posted by Les

Yes, think you need a new pump for wb testing
Have you got PayPal account - will happily donate 35 GBP (or 456 SEK ) towards a purchase.
Let me know, please.

Hoping may produce result something like this :-



The MCW 6000 prediction is an extension of this discussion and is 0(TIM) and 0(offset).

Thank you for the offer Les.

Would you have any particular suggestions? I have not really been paying close attention to the pump threads so I have no real idea of what is capable of what. I note that Cather has been busy but am not sure that is quite pertinant for this scenario.
I do like quiet.