Critical behaviour in chemically reacting systems

The Semenov theory of thermal explosion without fuel consumption cannot be derived correctly from the exact equations describing the problem, i.e. the equations with fuel consumption. The limiting process used to derive the former from the latter (ε{lunate} → 0, B → ∞) is shown to involve an infinite stretching of the dimensionless time coordinate. A correct limiting process is given which provides different equations from the Semenov theory.