In the context of a rocket engine, the term “nozzle exit” typically refers to the point at which the high-speed exhaust gases exit the rocket nozzle into space. The total energy at the nozzle exit for a rocket engine is the sum of the enthalpy and kinetic energy of the exhaust gases.
The static enthalpy includes the internal energy, pressure energy, and potential energy of the exhaust gases at rest (i.e., static) just before entering the rocket nozzle.
Understanding the total energy at the nozzle exit is crucial for analyzing the energy available to produce thrust and accelerate the rocket. Specific values for these parameters depend on the specific conditions, propellant, and design of the rocket engine.
The total energy () at the nozzle exit can be expressed as:
where,
- E is the Total Energy, i.e sum of kinetic and potential energy
- is the static enthalpy at the nozzle exit,
- is the velocity of the exhaust gases relative to the reference frame of the exhaust gases