Lagging ignition of combustible fluids in porous media—effect of fuel supply rate*

The effect of fluid leakage into insulation material is considered, where the combustible fluid spread over the inner fibres of the material is both slowly oxidizing and undergoing evaporation/desorption. It is found, in particular, that the constant supply of fuel can lead to unexpected oscillatory behaviour in regions of parameter space which would otherwise have been considered safe. In particular, the case of an extremely slow rate of supply of fluid can be the most deceptive in terms of the possibility of ignition.