In the present paper the authors propose a pattern of calculation permitting to predict the thermal evolution of a gas‐fluidized system, which is mechanically stirred and subjected to abrupt fluctuations of the speed of the agitator. The two following cases are studied:
a full‐fluidized system.
a partly‐fluidized system involving a dense portion of wall layer.
The present work permits to confirm the results obtained from the mechanical and thermal studies performed in a steady state(1,2); it also gives a valuable tool for designing automatic control systems intended for regulating the temperature of heterogeneous layers.