The study of the relationships between work, heat, energy, and temperature, is known as thermodynamics.
The laws of thermodynamics describe how energy changes in a system and whether or not the system can do useful work on its surroundings.
Throttling process in thermodynamics
The process of throttling involves utilizing a throttle valve to change a high-pressure fluid into a low-pressure fluid.
Throughout the throttling process, enthalpy is constant and work is negligible.
And it is a very fast process so it is considered in an adiabatic process. Enthalpy is constant because no work is done on the system and there is no heat transfer into the system.
Throttling is the process of limiting fluid flow by just partially closing the valve. As the bell rings, let's imagine there are pupils in the room, and they start to depart. Now the pupils will group together if the door is just partially opened.