Quote:
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Originally Posted by Incoherent
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The problem is, fitting theory with pHaestus' testing gives values for h which are very high in my opinion. For the Cascade and MCW6000 we are talking values between 50,000 and 150,000W/m^2*C depending on flowrate. This feels wrong to me. But Cather has demonstrated numbers well over 100,000 in his testing so I don't quite know what to think. For the MCW5000 and #rotor blocks the numbers are in the region of 10,000-30,000, showing that they are a fundamentally different type of block.
Guesses all but somewhat grounded in the region between reality and theory.
Incoherent
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A couple of thoughts.
I guess you are referring to "h(eff)" and not "h (convection coefficient)"
This is very similar to "h(bp/Fin Interface)" that I have used, for example,
here.
In this case I do not disagree with the numbers IF "C/W(TIM)"=0.1
The suggestion that "C/W(TIM)"=0.1 is very iffy
It is based on the unsatisfactory suggestion that "tc offset in the bp ~ 0.001c/w " in the measured "C/W(TIM)" ~0.15c/w obtained by
Billa
The most inadequate analysis is :-
"The 0.15c/w consists of three components:
1) The tc offset in the die ~ 0.05c/w ( 2mm thick, 10x10mm Xsection
channel)
2) The tc offset in the bp ~ 0.001 - 0.05 depending on the the amount of
heat-spreading.(2mm thick, 80x50mm Xsection channel(surge) - 2mm thick,
10x10mm Xsection channel)
3) The Die/Goop/Bp interface."
This has not been modified since off-line discussions following
this.
Changing "tc offset in the bp ~ 0.001c/w" to "tc offset in the bp ~ 0.02c/w" would ,perhaps, mean "Sieder -Tate calculated h(convection coeff)" values are adequate :
From
here
The "Side to Side" uses "Sieder- Tate"