Thermodynamics is a branch of science that deals with the study of the behavior of heat and thermal energy. This subject is important in engineering because it provides criteria for processes under given set of conditions. Thermodynamics evolves in Laws that can be used to predict the direction in which a process would proceed and is proven to be helpful in engineering practice. 

Thermodynamics is a branch of science that deals with the study of the behavior of heat and thermal energy. This subject is important in engineering because it provides criteria for processes under given set of conditions. Thermodynamics evolves in Laws that can be used to predict the direction in which a process would proceed and is proven to be helpful in engineering practice. 

First Law of Thermodynamics

First Law of Thermodynamics is an expression of the principle of conservation of energy which states that energy can not be created or destroyed but can only be transformed or changed from one form to another.

 

Properties of Thermodynamic Substance

Before we go any further in our discussion, let us first discuss some fundamental concepts in Thermodynamics which includes Pressure and Temperature.

Thermodynamic System

Thermodynamic system or also known as control volume is defined as a region in space that is under consideration, it also contains mass or a thermodynamic substance. It has specific boundaries that separate it from the external effects of the environment.

Continuity Equation and Bernoulli's Theorem

In the First law of Thermodynamics, we learned that energy cannot be created nor destroyed, but can only be transformed or changed from one form to another. That concept is the same with mass. Conservation of mass states that the mass going IN the system is equal to the mass going OUT of the system. 

Pure Substances

Properties of Steam

Pure substances can be recognized by the constant nature of their properties and cannot be further purified. It can exist in more than one phase, but its chemical composition remains the same in each phase.

Reading Steam Tables

Steam tables are widely used by engineers and scientists in design and operation of equipment where steam is used as working substance in a thermodynamic processes and cycles. It gives an idea about the phase of steam at various temperature and pressure. 

Ideal Gas Equation

Equation of the state is a mathematical relationship among three intensive thermodynamic properties namely: pressure, specific volume and temperature.

Thermodynamic Processes

Thermodynamic process is a change of state of the thermodynamic substance in a system from initial state to final state. A reversible process is when a thermodynamic system is capable of restoring its original state by reversing the factors responsible for occurrence of the process. The irreversibility is the characteristic of the system which forbids it from retracing the same path upon reversal of the factors causing the change of state. Presence of friction, dissipative effects, etc., are caused of irreversibility.


 

Second Law of Thermodynamics

Second law of thermodynamics states that not all energies used in a thermodynamic system is converted into equivalent amount of work – some energy is always wasted. This law demonstrates the impossibility of perpetual machines.        

 

Carnot Cycle and Third Law of Thermodynamics

Nicolas Leonard Sadi Carnot (1796 - 1832), a French engineer, proposed a reversible cycle, which is named after him - the Carnot cycle.