Thermodynamic - System, Surrounding, Boundary

If we want to do analysis properly on thermodynamic related things, we must devid the thing in three part. They are as below....

1. System

2. Surrounding

3. Boundary

1. System :

Thermodynamic system is a specified region in which we are concentrated for thermodynamic analysis. Or we can say that system is a volume of space containing the item chosen for thermodynamic analysis. The system and its boundary are always chosen by us while doing analysis. A system does not have to be fixed in space. It can move, deform and increase or decrease in size with time. Basically there are three different types of system...
1. Close System
2. Open System
3. Isolated System.

1.1  Close System :

It is a part of system in which mass does not cross the system boundary. But energy may cross system boundary.

This fundamental diagram shows the property of closed system. i.e. in this system only energy can transfer across boundary of system.

 

                             

                                       Closed System (a)

             Closed System (b)

These are the examples of closed system of thermodynamics. fig (a) shows one testing tube in which hot water takes about 75 degree. and in that we knows that glass is good conductor of heat, so in that heat is transfer from water to glass. but the volume of water is constant in test tube. So (Heat) Energy transfer without transfer of mass. Fig (b) shows one plastic jar. also plastic is a good conductor of heat. In this case also (Heat) energy can transfer without transfer of mass.

1.2  Open System :

It is a system in which, both mass and energy may cross system boundary.

This fundamental diagram shows the property of open system. i.e. In this system energy as well as mass can cross boundary of system.

           

Open System (a)

Open System (b)

These are some example of Open System of thermodynamics. Fig (a) shows one cup filled with hot coffee. Here we consider coffee mug with hot coffee as a system. In this case heat is transferred from coffee mug in to atmosphere as well as steam is evaporated from coffee. So heat as well as mass is transferred from system. Thus it called open system. Fig (b) shows a part of steam power plant i.e. Turbine. In this case mass is entering from one side and leaving from other side, and also heat enery is exchang between turbine and surrounding atmosphere. Thus is also called a Open System.

1.3  Isolated System :

It is a system in which, both mass and energy may not cross system boundary.

                        

                                     Isolated System (a)

   Isolated System (b)

Fig (a) shows fundamental diagram of the property of open system. i.e. In this system energy as well as mass cannot cross boundary of system. Fig (b) shows perfectly insulated Thermos. Which is the perfect example of Isolated System. In this case mass as well as energy are not crossing the system boundry. Thus it is called as Isolated System.

2. Surrounding :

If we want to learn simply about surrounding, then remember one thing, "OUTSIDE THE SYSTEM IS SURROUNDING".  But we have to remember one thing that surrounding also has one limited boundary.

For ex :
Suppose we performing an experiment of boiling water in properly air-conditioned room. Then our system is water, and surrounding for this system is cool air. we cannot consider outside room air as a surrounding. So Surrounding itself has boundary.

3. Boundary :

Boundary is nothing but an imaginary line which separates system and surrounding. Boundary is always shown by dotted lines across system. Heat and mass can cross this line to do some useful work.

Or if you understand more about system surrounding boundary you can watch the video (link given below) to understand more about it.

       https://www.youtube.com/watch?v=7BKllTsXhm0&feature=youtu.be

Thank You.

What is ENGINEERING THERMODYNAMICS...?

The term thermodynamics is derived from the Greek Word therme (heat) and dynamics (power or motion); thus thermodynamics means heat power or heat in motion. Thermodynamics is defined as the science of engineering that deals With the storage of energy, entropy, heat and Work, mutual conversation of heat and Work, exchange of energy and those properties of substances that govern the relation between heat and Work. Earlier, thermodynamics Was considered as a subject of science by Joule (1818-1889), Kelvin (1824-1907), Clausius (1822-1888) and Carnot (1792-1832). Later, Gibbs (1839-1903) extended its scope and now it is extensively used in branches of science and engineering to analyze physical and chemical changes. Experimental observation is the basis for thermodynamics. Based on these observations and results, certain basic laws are developed Which are known as the Zeroth, First, Second and Third laws of thermodynamics. A large part of the subject of thermodynamics deals With a study of energy. Energy can be defined as a capacity to produce change. The energy output of an I.C. engine supplies the capacity to move from one location to another. The energy output of a power plant supplies the capacity to produce a Wide variety of changes to operate motors, television sets and lights, etc.

Thermodynamics is the science of energy transfer and its effect on the physical properties of substances. It is based upon observations of common experience which have been formulated into thermodynamic laws. These laws govern the principles of energy conversion. The applications of the thermodynamic laws and principles are found in all fields of energy technology, notably in steam and nuclear power plants, internal combustion engines, gas turbines, air conditioning, refrigeration, gas dynamics, jet propulsion, compressors, chemical process plants, and direct energy conversion devices.

Or else you want to learn more about thermodynamics or you want to learn, what things are present in thermodynamics, you can see this video given below..

https://www.youtube.com/watch?v=9GMBpZZtjXM&list=PLD8E646BAB3366BC8

Thank you.