Oxidation and Heat Transfer Studies in Graphite Channels: IV. Combined Effects of Temperature, Flow Rate, Diameter, and Chemical Reactivity on the Length of Channel Cooled by Air

The activation energy for graphite oxidation was obtained from the change in the “stable length” of channel with temperature. The maximum temperature at which thermal equilibrium (between the heat generated by graphite oxidation and the heat removed by the air stream) will occur in a channel can be predicted from the heat transfer coefficient, the activation energy, and a single value of the graphite reactivity at any temperature. Above this maximum temperature, the total length of channel is thermally unstable. An equation is given expressing the length of channel that can be cooled as a function of temperature, flow rate, diameter, and reactivity.