1. Introduction to Conduction
By applying an energy balance to a control volume, we acquire the governing equation for heat transfer due to conduction:
Where:
is the internal thermal energy of the material.
is the energy supplied due to an applied heat flux.
is the energy generated due to the rate of thermal energy generation.
Substitute in Fourier's Law
:
If incompressible, and therefore:
If one dimensional conduction, and assuming the specific heat
is constant:
If no heat generation,
:
If steady-state, then , giving the heat equation:
Boundary Conditions
The heat equation is second order, therefore two boundary conditions must be specified. There are various scenarios for this:
Constant temperature:
Applied flux:
Ideally insulated, with no applied flux:
Â
If the surface is in contact with fluid, Newton's law can be applied: