Extended Surfaces (Fins)

Extended Surfaces or Fins are sections of an object that extend out into a fluid used for heat dissipation. They are covered in Section 3.6.

General form of energy dissipation equation for a fin (Eq. 3.66):

In the above image the cross section does not change along the length of the fin, thus the general equation can be reduced to the following (Eq. 3.67):

The following two definitions (Eq. 3.68 & 3.70):

allow us to reduce our equation (Eq. 3.69):

Now that it is in this form we can find it's general solution to be (Eq. 3.71):

We generally refer to as a temperature difference.

A derivation for a rod fin can be found in 4E - Class 2 - Fins Cont. 2024-02-13 00_10_36

Hyperbolic tribometry functions (namely ) appears frequently. This is due to it's definition:

See extended-surface-equation-table for equations related to extended surfaces.

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