ABSTRACT

The principal goal of this chapter is to describe the derivation of a formula for the temperature rise of steady airflow with a constant rate of heat input over a section of a duct. This duct is our representation of a circuit board or a plate-fin heat sink channel. The result is so commonly used that you should, at least once in your life, see how the equation comes about. Surprisingly, the derivation is often omitted from both heat transfer texts and reference books on electronics cooling and, although I would like to take credit for the effort, you should know that the work is taken from one of J.P. Holman’s excellent books (see Holman, 1974).