Chapter 3: Conduction in Plane Walls, Cylinders, and Fins

This chapter focuses on heat conduction through plane walls, composite systems, and the use of extended surfaces called fins to improve heat transfer. It starts by describing one-dimensional steady-state conduction through a wall without internal heat generation, where temperature drops linearly across the wall. The thermal resistance model is introduced, using formulas similar to those in electrical circuits, allowing resistances to be added in series or in parallel for multilayered or composite structures. Cylindrical and spherical conduction are then covered, with formulas adapted for radial geometries. The chapter then shifts to fins, which increase surface area to enhance convective heat loss. Important variables such as fin perimeter, cross-sectional area, and surface area are defined, leading to the development of the fin parameter m and performance metrics like effectiveness and efficiency. The corrected fin length accounts for tip convection. A step-by-step strategy is provided for solving wall and fin problems, including geometry identification, applying boundary conditions, and verifying physical accuracy. A cheat sheet at the end summarizes all major equations and concepts for quick reference.