System and Control Volume

A system is a part of the universe under study. Everything in the universe, other the system, is called surrounding. A boundary separates the system from the surroundings, as shown below. Systems can be considered as closed or open.

Figure: System and surroundings [1]

Figure: Open system and closed system [2]

A closed system, also called a control mass, consists of a fixed amount of mass, and no mass can cross its boundary. However, energy can enter or leave the closed system, and the closed system can have moving boundaries, or it can move around. An open system, also called a control volume, is a fixed region in space. Energy and mass can enter or leave the system. Both, open and closed systems are shown in the figure above.

At this stage, students are recommended to read the first chapter of the book: Cengel, Y.A., 2010. Fluid mechanics. Tata McGraw-Hill Education.

References:

1. https://www.toppr.com/guides/chemistry/thermodynamics/application-of-thermodynamic-terms/ [Accessed on: 13/07/2018]

2. http://www.hkdivedi.com/2016/08/difference-between-isolated-and-non.html [Accessed on: 13/07/2018]