Control volume in a thermodynamic system refers to-

Concept:

• A control volume is a fixed, identifiable region in space through which fluid flows.
• The boundary of the control volume is called a control surface.
• Types of System

Control Mass System (Closed System)

• It is a system of fixed mass with a fixed identity
• This type of system is usually referred to as "closed system"
• There is no mass transfer across the system boundary
• Energy transfer may take place into or out of the system

Control Volume System (Open System)

• It is a system of fixed volume
• This type of system is usually referred to as "open system” or a "control volume"
• Mass transfer can take place across a control volume
• Energy transfer may also occur into or out of the system
• A control volume can be seen as a fixed region across which mass and energy transfers are studied
• Control Surface- It is the boundary of a control volume across which the transfer of both mass and energy takes place
• The mass of a control volume (open system) may or may not be fixed