May 26, 2021

Thermodynamics Systems and The Laws

When a matter is separated from its surrounding by some means of walls then that matter is called a system and when that system is observed in terms of heat and mass transfer then that system became a thermodynamics system. So a thermodynamics system is one in which a matter is separated from its surrounding by means of wall called boundary and is observed in terms of heat and mass transferred between system and surrounding through boundaries at certain conditions. There three types of thermodynamics system; isolated system, close system and open system and when external forces like force and heat is applied on system it is called thermodynamics operations. These operations are controlled by the means of three thermodynamics laws. Thermodynamics operation involve the external forces, work done, heat energy and transfer of mass between system and surrounding through boundaries. When a thermodynamics operation is performed on a system then its properties like internal energy, enthalpy, entropy, pressure, volume and temperature is changed. This change is governed by thermodynamics laws and happens to make the system in thermodynamics equilibrium.

According to first law of thermodynamics; heat can neither be generated nor be destroyed but it ca be changed from one form of energy to another form of energy. Therefore this law of thermodynamics is called the law of conservation of energy. In energy generating power plants the first law of thermodynamics govern the mechanism of energy transfer and energy generation. As per law energy cannot be created to generate energy in power plant, an energy source is needed. As per law energy is converted from one form to another form, so to get electrical energy of heat energy the initial form of biomass have to convert into other form of energy. This conversion of biomass energy into heat energy can be done through thermodynamics operations, which changes system properties governed by the thermodynamics laws.

A perfect gas or also known as the Ideal gas is one which fully follows the thermodynamics process and laws and does not show any divergence from them. An ideal gas will show perfect relationship of three main properties of a system that is relationship between pressure, volume and Temperature. In an ideal gas case at any point of the system the following relation can be find true


B) Polytropic index

The polytropic index for a process that changes its state from point 1 to point 2 can be calculated as follow


So the polytropic index of the following system is 1.3 and it will remain same for  each and every stage of the system.

c) Work done

Work done in polytropic can be calculated as follow

Work= W=(P2V2-P1V1)/(1-n)

In above result the work done is positive which show that work in done by the system. If the work result were negative then it show that work was done on the system (energy is being added into the system)

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