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eveS
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I am analyzing the lengthwise temperature distribution in a cooling fin (length: 30mm, width: 10mm, the tip is assumed to be adiabatic, Biot number is smaller than 0.1).
When I try to calculate the dimensionless temperature distribution (see calculation below), I obtain a curve which has a minimum at about 2/3 of the fin length and increases again after that (see attachment).
I don't understand why the temperature should increase again towards the tip of the fin. Using Ansys to model the fin I obtained the other curve in the graph, which shows decreasing temperatures towards the tip of the fin (and makes more sense to me).
I don't know whether I am making a mistake in my calculations, or whether there is a simple explanation.
Any advice would be appreciated!
calculation:
distribution "theta" (x) = cosh(m*(1-x/L)) / cosh(m) ,
where m= sqrt [ ( P*L*h) / (A*k) ]
L=length
P=perimeter
A=area
h=heat transfer coefficient
k=thermal conductivity
When I try to calculate the dimensionless temperature distribution (see calculation below), I obtain a curve which has a minimum at about 2/3 of the fin length and increases again after that (see attachment).
I don't understand why the temperature should increase again towards the tip of the fin. Using Ansys to model the fin I obtained the other curve in the graph, which shows decreasing temperatures towards the tip of the fin (and makes more sense to me).
I don't know whether I am making a mistake in my calculations, or whether there is a simple explanation.
Any advice would be appreciated!
calculation:
distribution "theta" (x) = cosh(m*(1-x/L)) / cosh(m) ,
where m= sqrt [ ( P*L*h) / (A*k) ]
L=length
P=perimeter
A=area
h=heat transfer coefficient
k=thermal conductivity