We establish three partial differential equation models describing the thermodynamic behavior of a fluid by combining energetic variational approach, appropriate constitutive relations, and classical laws. By using an explicit algebraic we show maximum/minimum principle for some auxiliary variables involving absolute temperature ? density ? under special conditions, which then yields positivity...

Sponge iron (DRI) due to the high surface area, often shows a high tendency to re-oxidation and at some cases spontaneous combustion (autoignition). In this work, re-oxidation behavior and autoignition of sponge iron, produced from different types of iron ore has been investigated. Isothermal and non-isothermal re-oxidation experiments were carried out on each type of DRI and their autoignition...