The inlet air velocity () for a turbofan engine refers to the speed of the incoming air at the entrance of the engine’s inlet. In a turbofan engine, air is drawn into the engine and is divided into two streams: one stream passes through the core of the engine (core flow), and the other bypasses the core, flowing around it (bypass flow).
The continuity equation is based on the principle of conservation of mass, stating that the mass flow rate remains constant in an incompressible flow. For a turbofan engine, this means that the mass of air entering the engine is equal to the total mass of exhaust gases leaving it, including the core flow and the bypass flow.
The continuity equation is based on the principle of mass conservation, and Bernoulli’s equation expresses the conservation of energy.
The continuity equation is given by:
where:
- and are the cross-sectional areas at the nozzle entrance and exit, respectively,
- and are the velocities at the nozzle entrance and exit, respectively.
which gives
where,
- A1 is the Cross-Sectional Area of Nozzle Inlet in m2
- A2 is the Cross-Sectional Area of Nozzle Exhaust in m2
- V1 is the Inlet air Velocity in m/s
- V2 is the Exhaust Air Velocity (core flow + bypass flow) in m/s