A hybrid-propellant rocket is a rocket with a rocket motor that uses rocket propellants in two different phases: one solid and the other either gas or liquid.
In the context of a hybrid rocket engine, the “nozzle exit” refers to the point where the high-speed combustion products exit the rocket nozzle. Hybrid rocket engines use a combination of liquid oxidizer and a solid fuel. The total energy per unit mass at the nozzle exit can be expressed as the sum of the enthalpy and kinetic energy of the combustion products.
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