Heat Transfer
Conduction, convection and radiation are three different physical mechanisms that all end up as a W/m² — and picking the wrong one is the most expensive mistake in the subject. These topics animate the mechanism before the correlation.
Start from the beginning →1 topic you can watch now, 22 still to come.
The three modes
Three mechanisms, three laws, one unit.
- Fourier's law and thermal conductivity
- Newton's law of cooling
- Stefan-Boltzmann law
- The general heat conduction equation
Conduction
Energy moving through a material that stays where it is.
- Steady conduction through slabs, cylinders and spheres
- Thermal resistance networks
- Critical radius of insulation
- Fins and fin efficiency
- Transient conduction and the lumped capacitance model
Convection
Energy carried away by fluid that is itself moving.
- Thermal boundary layer
- Dimensionless numbers: Re, Pr, Nu, Gr
- Forced convection over plates and in tubes
- Natural convection
- Boiling and condensation
Radiation
Energy crossing a vacuum, with no material involved at all.
- Black body radiation and emissivity
- Kirchhoff's law and grey surfaces
- Shape factors
- Radiation exchange between surfaces and shields
Heat exchangers
Where all three modes are put to work on purpose.
- Parallel, counter and cross flow
- LMTD method
- Effectiveness-NTU method
- Fouling and overall heat transfer coefficient