Question

What are the types of boundaries in thermodynamics?

Answer 1

Thermodynamics is a matter or radiation confined in the space walls with the defined Permeability.
An isolated thermodynamics system has walls that are non-conductive of heat and perfectly reflect all radiations.
The closed thermodynamics system is impermeable to matter.

Complete step-by-step solution:
Thermodynamics is defined as the study of energy and energy transformations and their relation to matter. The analysis of thermal systems is achieved through the application of the governing conservation equations they are conservation of mass, conservation of energy.
The surface that separates the system and the surrounding is known as the Boundary this boundary may be fixed or movable.
The thermodynamics system classification is based on the nature of the boundary and the flow of the matter, energy, and entropy.
The isolated system does not exchange heat with the environment. The example of the isolated system is an insulated container like an insulated gas cylinder.
$${E_{in}}{\text{ = }}{E_{out}}{\text{ = 0}}$$${\operatorname{m} {in}} = {m{out}} = 0$${\operatorname{m} {in}} = {m{out}} = 0$
The example of the fixed boundary is gas cylinders, the example of the movable boundary is moving engines. The boundary can expand or contract itself. This is known as the flexible boundary
We have to be clear about the control volume and control mass to understand the fixed and movable boundary. The control mass is the boundary of a system hence mass that cannot be changed is called the control-mass boundary.
there are four boundaries in thermodynamics:
Fixed boundary conditions
Movable boundary conditions
Real boundary conditions
Imaginary boundary condition

Note: An example of a flexible boundary is the piston device of the ic engine. when the piston moves the boundary expands but the mass of the gas inside the cylinder remains constant.
The real boundary is the boundary that separates the system from the universe. An Example of the real boundary is a glass of water.
The imaginary boundary separates the system from the universe.
The Movable boundary allows the energy transfer because of the boundary work.