2020.06.14(pm): fin efficiency and fin effectiveness

Heat transfer is an area that deals with changes in temperature and the flow of heat energy. There are three basic mechanisms of heat transfer: conduction, convection, and radiation.

Conduction
It is the transfer of energy from active particles to neighboring more active particles by the interaction of particles in the object.

Convection
Heat transfer between a solid surface and a moving fluid (liquid or gas) results from a complex effect of conduction and fluid motion in the fluid.

Radiation
It is the transfer of energy emitted from an object in the form of electromagnetic waves or photons due to changes in the arrangement of electrons in an atom or molecule.

Aside from the fundamental story of heat transfer, today I want to explain the efficiency and performance of fins. We can often see fins in our lives. For example, fins are also used for heat sinks attached to handling micro development boards and heat sinks to prevent overheating of the computer’s motherboard.

Aluminum Heat Sink IC Heatsink Cooling Cooler Fin For CPU LED ...
aluminum fin

The fin serves to dissipate the heat received by the machine using a material with high thermal conductivity and consequently protects the machine from overheating. So how is this fin’s efficieny determined?

fin

If the length is infinite, boundary condition is :

heat transfer of conduction is :

heat transger of convection is :

so, sum of heat transter is :

fin efficiency

straight fin of uniform cross-sectional area with an adiabatic tip

fin effectiveness

And usually, if this value exceeds 2, it is considered reasonable.