In the analysis of unsteady flow, or transient flow, processes, the system is abandoned in favour of a control volume. Attention is given to a fixed region in space, not to a fixed mass in motion. The control volume, defined by an imaginary closed boundary, is set up to surround the equipment under study. Both mass and energy may cross the boundary.
What is the difference between Upright Cylindrical Vessel and Spherical Vessel?
Pressure vessels are generally used for storing steam at high pressure. There are many types of pressure vessels in which the commonly applicable pressure vessels are following.