A general model of foaming has been developed which relates the structure of a foam stabilised by viscoelastic forces to the bubble rupturing processes. For the specific case of negligible bubble coalescence within the foam it has been shown that, in the region of linearity between the foam height and gas flux, the residence time of gas in the foam (Σ) is solely a function of the bubble diameter (d), the liquid phase density (ρ) and viscosity (μ), and the effective elasticity (E_eff) resulting from the dynamic adsorption of surface active species:

Σ=1×106((pg)2d3 μ·Eeff)

The model, which shows that the gas bubble diameter has the greatest effect on the retention of gas bubbles within the foam, has been found to be applicable to a range of system in which foams are stabilised by viscoelastic forces.