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Diffusion models of multicomponent mixtures in the lung. (English) Zbl 1202.76106

Summary: We are interested in two different diffusion models for multicomponent mixtures. We numerically recover experimental results underlining the inadequacy of the usual Fick diffusion model, and the importance of using the Maxwell-Stefan model in various situations. This model nonlinearly couples the mole fractions and the fluxes of each component of the mixture. We then consider a subregion of the lower part of the lung, in which we compare the two different models. We first recover the fact that the Fick model is enough to model usual air breathing. In the case of chronic obstructive bronchopneumopathies, a mixture of helium and oxygen is often used to improve a patient’s situation. The Maxwell-Stefan model is then necessary to recover the experimental behaviour, and to observe the benefit for the patient, namely an oxygen peak.

MSC:

76M25 Other numerical methods (fluid mechanics) (MSC2010)
92C35 Physiological flow
76Z05 Physiological flows
35K57 Reaction-diffusion equations
76T99 Multiphase and multicomponent flows
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