Question

There are three heat transfer mechanisms. Define each type and briefly explain how they work. Additionally define insulation and how it contrasts against these transfer mechanisms

Answer 1

The three heat transfer mechanism are:

Heat transfer by Conduction

The mechanism of heat transfer by conduction occurs at the atomic scale through matter (solid state) by molecular activity, by the collission of some molecules with others, the more energetic molecules give energy to the less energetic producing a flow of heat from the temperatures more high to the lowest. A model for conduction heat conduction can be:

Which is called the Fourier heat conduction equation.

Heat transfer by Convection

This mechanism occurs by movement of mass or circulation within the substance. It can be natural produced only by differences in density of matter; or forced, when matter is forced to move from one place to another. It only occurs in liquids and gases where the atoms and molecules are free to move in the middle. A model for convection can be described as:

Heat transfer by Radiation

Unlike the two previous mechanisms, heat transfer by radiation does not need a material means to propagate. The heat is transferred by means of electromagnetic waves or by photons.

For the case of insulation, its purpose is to prevent heat transfer from occurring. So, the type of insulation will depend on the heat transfer mechanism that is being studied. A type of insulation for convection does not work for radiation for example.