Heat Transfer
Heat transfer lectures by Professor Josua Meyer (2014). Topics covered in the lectures include: transient or unsteady heat conduction, convection heat transfer, external and internal forced convection, heat exchangers, thermal radiation including atmospheric and solar radiation. The lectures are based on the textbooks of White (8th ed) and Cengel and Ghajar (4th ed) and were presented as part of a heat transfer class to the fourth year students of the Department of Mechanical and Aeronautical Engineering, University of Pretoria.
| Lecture 04 - Transient Heat Transfer: Lumped System Approach |
This lecture is an introduction to transient or unsteady heat conduction with emphasis on the lumped system approach. This lecture focuses on the Biot number and what it represents and when it can be used. Two examples were discussed and the focus was specifically on the ratio of the two resistance terms; the conduction resistance and the convection resistance. The strictness of the Biot number value of 0.1 was also highlighted. The characteristic lengths of plane walls, long cylinders and spheres were also derived and attention was given to the fact that these characteristic lengths were only value for the lumped system approach.
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