Derivation process? (Heatsink Fin Heat Conduction Equations)

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SUMMARY

The discussion focuses on the derivation of the heat conduction equations for fins, specifically addressing the confusion surrounding the inclusion of constants in the equations. Participants clarify that the right side of the equation represents the rate of heat transfer at the fin tip, which is equivalent to the rate of heat transfer at x=0 under steady-state conditions. The equation involves the term sqrt(hpkA)(Tb-T_inf), which is derived from the boundary conditions applied to the fin's temperature profile. The differentiation of θ(x) with respect to x is confirmed to be valid since T_inf is treated as a constant.

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  • Understanding of heat conduction principles
  • Familiarity with fin heat transfer equations
  • Knowledge of boundary conditions in thermal analysis
  • Basic calculus for differentiation of temperature profiles
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  • Learn about boundary conditions in steady-state heat conduction
  • Explore the application of the Fourier series in solving heat conduction problems
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EastWindBreaks
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Homework Statement


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I don't understand the derivation of the right side of the last equation.

Homework Equations

The Attempt at a Solution



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I got to this point, I also don't understand why it did not include C_2 for the variation of temp. along the fin.
I am guessing the right side is the rate of heat transfer on the tip? which equals to the rate of heat transfer at x=0 under steady state. but i failed to see how they are equivalent, I don't understand where did sqrt( hpkA)*(Tb-T_inf) came from. any help would be appreciated!

 

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Your second equation should be θb = θ(0) = C1 + C2, instead of 2. and since C1 = 0, C2 = θb. Now when you differentiate θ(x) wrt x and multiply both sides by -kA at x=0, it should work out OK.
 
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Dr Dr news said:
Your second equation should be θb = θ(0) = C1 + C2, instead of 2. and since C1 = 0, C2 = θb. Now when you differentiate θ(x) wrt x and multiply both sides by -kA at x=0, it should work out OK.
thank you, I got it now. the reason we differentiate θ(x) is because T_inf is treated as a constant right? therefore it is same as dT/dx.
 
Last edited:
That is correct.
 
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