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Unread 09-21-2005, 06:31 PM   #92
Les
Cooling Savant
 
Join Date: Oct 2001
Location: Wigan UK
Posts: 929
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Returning to h(eff)
Have 2 methods for determining the Heat Tramsfer Coeeficient(h(conv)): (1) Sieder-Tate for channels(Kryotherm) (2) Flomerics for impingement.
Use both for the WW then convert to h(eff)**
Presented, in earlier post, the "Sieder-Tate model" which concurs with your postulate.
However the "Flomerics model" predictions.are still a better fit to the only data available - Billa.
Originaly the predictions were matched to the exerimental by adding C/W(TIM)=0.1c/w. However the sensor offset of ~0.05c/w was overlooked. The upshot is that with the accepted C/W(TIM)=0.06c/w and ~0.05c/w offset the "Flomerics model" is the better fit.
With the at-time-evidence pointing to bp<1mm being best at all flow rates the "Flomerics model" was and is still the preferred

Have attached the "Flomerics model" predictions.This suggests that at ~6watt (~ 10lpm P/Q link)
the h(eff) is ~ 90-100kw/m^2c and not 60-70kw/m^2c.
With no10x10mm die test data and no model(to connect h(conv) and h(eff)) for the Storm or Cascade think your suggested h(eff) values are a big Dunno.

** I use Kryotherm to convert h(conv) to h(eff) ...............h(eff) is the effective heat transfer coefficient acting on the finned surface of the bp(as defined here)
Then use Waterloo to convert h(eff) to Thermal Resistance(rather loosely designated C/W).

EDIT: Corrected Flomerics Prediction graph and edited text accordingly (in magenta)
Was using a "memory version" for (heff)
Found my Excel for predicted h(eff) of "Production WW"
Attached Images
File Type: jpg Fantasy1.jpg (40.2 KB, 7 views)
File Type: jpg Fantasy2.jpg (38.2 KB, 8 views)

Last edited by Les; 10-04-2005 at 06:52 AM.
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