What is the throttling process in thermodynamics?

Answer: A throttle valve is used to change a high-pressure fluid into a low-pressure one during the throttling process. The enthalpy stays constant and there is no work done during a throttling operation. Throttling cannot be an isentropic process. Fundamentally, the process is irreversible. Process of throttling characteristics: 

1. No transfer of work
2. No transfer of heat 
3. It is an irreversible process 
4. It is an isenthalpic process 

Because a throttling device creates a local pressure loss, restricting the flow results in a considerable drop in pressure. Simply adding a restriction to a line through which a gas or liquid flows might cause throttling. Commonly, a porous plug or a partially open valve are used to impose this constraint.