Transport and diffusion processes are central in numerous scientific and technical applications. Prominent examples are the temperature distribution in continuous media, the flow of liquids or gases, the dynamics of reaction-diffusion systems, or the concentration distributions in mixtures. The theoretical and numerical description of these systems is based on partial differential equations. The theory of non-equilibrium thermodynamics provides a frame to derive these equations from basic conservation laws and first principles. The first part of the textbook discusses the concept of equilibrium thermodynamics and its generalization to systems in local equilibrium. Thermodynamic fluxes are defined and caused by generalized forces. Finally, linear relations, the Onsager relations, between fluxes and forces allow for a closed description. In this way, conservation equations for mass (continuity), momentum (Euler or Navier-Stokes), and energy (temperature) are derived and solved analytically or numerically for several examples. The second part is based on the kinetic gas theory describing a classical many particle system. At the example of a perfect gas the conservation equations derived phenomenologically in the first part are thereby put on statistical grounds. The textbook addresses advanced Bachelor or Master students of physics, mechanical engineering and applied mathematics.
