Classification of thermal systems
According to the energy and material exchange between the thermal system and the outside world, the thermal system can be classified as follows:
① Opening system: a thermal system where the system has both material exchange and energy exchange with the outside world. Both energy and mass can be changed in an open system, but this change usually occurs within a defined range, so it is also called a controlled volume, or a controlled volume system.
② Closed-mouth system: a thermal system in which the system exchanges energy with the outside without material exchange. The quality in the closed system remains constant, so it is also called the quality control system.
③ Adiabatic system: a thermal system with no heat exchange between the system and the outside world. Regardless of whether the system is open or closed, as long as no heat crosses the boundary (the system has no heat exchange with the outside world), it is an adiabatic system.
④ Isolation system: a thermal system in which the system has neither energy exchange nor material exchange with the outside world. All interactions of an isolated system occur inside the system and are completely unaffected by the outside world. Isolated systems do not exist in nature. Isolated systems are an abstract concept in thermodynamics research.