Equation 1

The basic formula for heating by convection (in one form) is given by Equation 1.

Fig. 1. Initial conditions for convective heating

Here’s how this formula is derived and used. We begin by establishing some initial conditions for convection heating (Fig. 1).

Fig. 2. General heating characteristics

Assume that we are heating in a batch-style furnace or oven where we have the following general heating characteristics (Fig. 2).

In practice, it is difficult to achieve the conditions for (11b), thus (12) is generally used for steel. For aluminum, the factor becomes 0.9 rather than 0.67.