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Originally Posted by Cathar
Well, it's the same definition, just worded differently.
The watts are constant, so they cancel out.
We're left with efficiency = Real C / Ideal C.
As bobo says, this is all minus tim and bp, aka, the surface temperature where the convection(conduction) is taking place. Since this is relative to the water's temp, it's the exact same measurement of efficiency that you referred to above Les, and that I was talking about.
I haven't had the time to dig further into Les's analysis of h(eff) yet. Will do so this weekend.
As for nusselt & stanton numbers, I'll leave that stuff to the theorists to quantify. h(eff) is pretty much all I'm concerned about as a means of assessing design performance.
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Well its (c/w) * Q as we are only concerned with water. Cp and rho drop out and the units are only constants * lpm for example. Considering how wb perform according to c/w = k/Q its more useful than c/w for a specific flow rate as a mesure of performance.
reading my heat transfer textbook its actually amazing how useful the stanton number is. Its effective non dimensional heat flux/ non dimentsional heat transfer coefficant. You could design a fairly good water block of just the stanton number and its member parts. st= nu/(re*pr)