In a steady flow process a fluid flow steadily through a control volume. At any point, fluid properties remain constant during the process. There are many engineering equipments which function as steady flow system.
In a cyclic system, energy cannot be stored in the system. If all the heat cannot be converted to work and no energy can be stored, some of the energy received must be rejected.
In a reciprocating IC engine, the combustion of the fuel occurs within the engine cylinder. The engine partially converts the heat of combustion to work.
Closed or non-flow process: This type of processes happens in closed system. No mass transfer takes place but, energy transfer in the form of heat and work may occur across the boundary.
If a closed system completes one cycle the cyclic integral of heat is equal to the cyclic integral of work. If a system completes a process, the change in stored energy of the system is equal to the net heat interaction minus the net work interaction during the process.
An ideal or perfect gas obeys the gas laws under all conditions of temperature and pressure. For practical purpose, gases are considered ideal when they behave quite accurately within some preselected region of temperature and pressure.
Energy is capacity to do work. It may exist in many forms. Energy within the system boundary is known as stored energy. Examples of stored energy are potential energy, kinetic energy, internal energy etc. Energy that in the process of crossing the system boundary is called energy in transition or transit. Examples Heat, work etc.
A Thermodynamic system is a quantity of matter, or a region selected for study and separated from everything by a boundary. So, a system is always associated with a system boundary. A boundary separates the system from its surroundings. Any mass or region outside the system is called surrounding.
Safety valve is a Boiler mounting for safety against high pressure. Fusible plug on the other hand is another Boiler mounting for safety. But Fusible plug is a safety mounting against elevated temperature due to low water level inside the Boiler.
Safety Valve is one of the Boiler Mountings for safety. It protects the Boiler against steam pressure higher than the working presure.