China
Africa
Explore chapters and articles related to this topic
Introduction and Basic Concepts
Published in Kavati Venkateswarlu, Engineering Thermodynamics, 2020
A system is said to be in thermodynamic equilibrium if it is in thermal, mechanical, and chemical equilibrium with itself and with the surroundings. Temperature and pressure at all points are the same and there should be no velocity gradient. Systems under temperature and pressure equilibrium but not under chemical equilibrium are sometimes said to be in metastable equilibrium conditions. It is only under thermodynamic equilibrium conditions that the properties of a system can be fixed. Thus for attaining a state of thermodynamic equilibrium, the following three types of equilibrium states must be achieved: (i) Thermal equilibrium: the temperature of the system does not change with time and has the same value at all points of the system. (ii) Mechanical equilibrium: there are no unbalanced forces within the system or between the system and surroundings. The pressure in the system is the same at all points and does not change with respect to time. (iii) Chemical equilibrium: no chemical reaction takes place in the system and the chemical composition, which is the same throughout the system, does not vary with time.
Some Definitions of Thermodynamics
Published in Jean-Louis Burgot, Thermodynamics in Bioenergetics, 2019
A system is in thermodynamic equilibrium when the values of the variables characterising the system do not change with time. The thermodynamic equilibrium entails that thermal, mechanical and chemical equilibria are simultaneously reached. This means that the temperature, pressure and concentrations must be identical in all the parts of the system. The state of thermodynamic equilibrium must not be confused with a stationary state (see Chapter 24, Open systems—some rudiments of non-equilibrium thermodynamics).
Temperature
Published in C.B.P. Finn, Thermal Physics, 2017
If two systems have the same temperature so that they are in thermal equilibrium, this does not necessarily mean that they are in complete or thermodynamic equilibrium. For this condition to hold, in addition to being in thermal equilibrium, they would also have to be in: mechanical equilibrium, with no unbalanced forces acting; andchemical equilibrium, with no chemical reactions occurring.
Intelligent computing through neural networks for entropy generation in MHD third-grade nanofluid under chemical reaction and viscous dissipation
Published in Waves in Random and Complex Media, 2022
Muhammad Asif Zahoor Raja, Rafia Tabassum, Essam Roshdy El-Zahar, Muhammad Shoaib, M. Ijaz Khan, M. Y. Malik, Sami Ullah Khan, Sumaira Qayyum
Entropy is a measurable physical attribute mostly linked with a condition or disorder, unpredictability, or uncertainty. It has many applications in biological systems, economics, sociology, meteorology, climate change, cosmology, and information systems, including telecommunications data transmission. Entropy has the effect of making specific processes irreversible. The second law of thermodynamics holds that the entropy of an isolated system left to spontaneous development cannot decrease with time because it always reaches a state of thermodynamic equilibrium, where the entropy is greatest. Using entropy optimisation, Alsaedi et al. [21] investigated the MHD TGNF flow by considering binary chemical reaction and activation energy past a stretching sheet. Hayat et al. [22] exemplified heat transmission in a mixed convective stream of carbon nanotubes with entropy generation subjected to a curved stretching surface. Under the influence of magnetic and electric fields, Khan et al. [23] explored EG in electro-magneto dynamical mixed convection flow. Nayak et al. [24] used EG to explore an MHD Hamilton’s Crosser flow by considering the Darcy-Forchheimer. The Jeffrey nanofluid stream under the effects of entropy generation was studied by Le et al. [25]. Using the Buongiorno model, Adnan et al. [26] evaluated the EG in a convective stream of hybrid nanofluid fluid using magnetic force impact. The EG was presented by Adnan et al. [27] in a nanofluid flow passing through convergent and divergent channels.