Thermodynamics is a science and, an important engineering tool used to describe processes that involve changes in temperature, transformation of energy, and the relationships between heat and work.
Thermodynamics where therme means “heat” and dynamics, means “power” is the study of energy conversion between mechanical work and heat, and the macroscopic variables such as temperature, volume and pressure.
It can be regarded as a generalization of an enormous body of empirical evidence. It is used to describe the performance of systems, power generation systems, and refrigerators, and to describe fluid flow, combustion, and many other phenomena.
For example: The focus of thermodynamics in aerospace engineering is on the production of work, often in the form of kinetic energy (for example in the exhaust of a jet engine) or shaft power, from different sources of heat.
The starting point for most thermodynamic considerations are the laws of thermodynamics, which postulate that energy can be exchanged between physical systems as heat or work. They also postulate the existence of a quantity named entropy, which can be defined for any isolated system that is in thermodynamic equilibrium.
Thermodynamics is based on two generalizations called the first and second law of thermodynamics which are based on human experience.
First law of thermodynamics, about the conservation of energy:
It states that energy can neither be created nor be destroyed. The change in the internal energy of a closed thermodynamic system is equal to the sum of the amount of heat energy supplied to or removed from the system and the work done on or by the system or we can say ” In an isolated system the heat is constant”.
Second law of thermodynamics, about entropy:
The total entropy of any isolated thermodynamic system always increases over time, approaching a maximum value or we can say “in an isolated system, the entropy never decreases”. Another way to phrase this: Heat cannot spontaneously flow from a colder location to a hotter area – work is required to achieve this.
