Definition of pressure balance
The pressure balance is divided into the pressure balance between the objects and the self-balancing of the individual phases. Pressure balance between objects Even under certain circumstances, the pressure between two directly or indirectly contact objects is balanced. The pressure balance of a single phase has a great relationship with its own thermal state. For example, the pressure balance of the free liquid surface is the dynamic equilibrium process of the liquid phase partial pressure and the liquid phase partial pressure of the liquid at the atmospheric pressure at that time. With the change of the external environment, The gas-liquid phase pressure balance will change accordingly. Therefore, the three-phase state in which physical properties are located is strictly considered when describing the pressure balance.