A turboshaft engine is a type of gas turbine engine designed to provide mechanical power rather than direct thrust for propulsion, as in aircraft. Turboshaft engines are commonly used to drive helicopters, certain types of marine vessels, and various industrial applications. The thrust force in a turboshaft engine is not the primary output; instead, the engine generates shaft power that is used to drive a rotor or other machinery.
The primary purpose of a turboshaft engine is to produce mechanical power, typically in the form of a rotating shaft. This shaft power is then used to perform work, such as driving a helicopter rotor or turning the propeller of a marine vessel. Unlike turbojet or turbofan engines, the emphasis in a turboshaft engine is on the extraction of mechanical power rather than creating forward thrust.
The thrust equation for a turbojet engine using control volume analysis is expressed as:
where,
- is the thrust force,
- ṁe is the mass flow rate of exhaust gases in kilograms per second (kg/s).
- is the Exhaust velocity at the nozzle exit in meters per second (m/s).
- ṁ0 is the mass flow rate of inlet gases in kilograms per second (kg/s).
- is the Exhaust velocity at the nozzle Inlet in meters per second (m/s).
- is the Pressure at the nozzle exit in pascals (Pa).
- is the Pressure at the nozzle inlet in pascals (Pa).
- is the Area of the nozzle exit in square meters (m²).