Special Session 120: Mixtures: Modeling, analysis and computing

Existence analysis of an evolutionary compressible fluid model for heat-conducting and chemically reacting mixtures
Milan Pokorny
Charles University
Czech Rep
Co-Author(s):    Miroslav Bulicek, Ansgar Juengel, Nicola Zamponi
Abstract:
The existence of large-data weak solutions to the evolutionary compressible Navier--Stokes--Fourier system for chemically reacting fluid mixtures is proved. General free energies are considered satisfying some structural assumptions, with a pressure containing a $\gamma$-power law. The model is thermodynamically consistent and contains the Maxwell--Stefan cross-diffusion equations in the Fick--Onsager form as a special case. Compared to previous works, a very general model class is analyzed, including cross-diffusion effects, temperature gradients, compressible fluids, and different molar masses. A priori estimates are derived from the entropy balance and the total energy balance. The compactness for the total mass density follows from an estimate for the pressure in $L^p$ with $p>1$, the effective viscous flux identity, and uniform bounds related to Feireisl`s oscillations defect measure. These bounds rely heavily on the convexity of the free energy and the strong convergence of the relative chemical potentials.