In reacting flow problems involving large numbers of chemical species and reactions, reduced chemistry modeling is used to approximately describe, with fewer unknowns, the slow chemical evolutions after the rapid but brief initial transients have decayed. Diffusion transport terms, if present, are modified by the reduced chemistry approximations. This article reiterates that the use of unmodifi...

The effects of fluid viscoelasticity on the expansion of gas bubbles in polymer foams for the cases of reactive and non-reactive polymers are investigated. For non-reactive polymers, bubble expansion is controlled by a combination of gas diffusion and fluid rheology. In the diffusion limited case, the initial growth rate is slow due to small surface area, whereas at high diffusivity initial gro...

The use of reaction-diffusion models rests on the key assumption that the diffusive process is Gaussian. However, a growing number of studies have pointed out the presence of anomalous diffusion, and there is a need to understand reactive systems in the presence of this type of non-Gaussian diffusion. Here we study front dynamics in reaction-diffusion systems where anomalous diffusion is due to...

diffusion models: A study of uranyl species diffusion" (2011). [1] Rigorous numerical description of multispecies diffusion requires coupling of species, charge, and aqueous and surface complexation reactions that collectively affect diffusive fluxes. The applicability of a fully coupled diffusion model is, however, often constrained by the availability of species self-diffusion coefficients, a...

When a polymer membrane containing an immobilized, reactive chemical is in contact with solution containing a reactive solute, the solute diffuses into the membrane and reacts with the immobilized chemical. As a result, the reactive solute and the immobilized chemical are consumed, and at the same time, mobile products may be produced within the membrane. The mobile products will diffuse out of...