The thrust force of a liquid propellant rocket nozzle can be calculated using the basic rocket thrust equation.
In a liquid propellant rocket, the mass flow rate of exhaust gases is influenced by factors such as the rate of propellant combustion and the efficiency of the combustion process. The exhaust velocity is affected by the nozzle design and the specific impulse of the rocket engine.
The design of the rocket nozzle plays a crucial role in optimizing the expansion of the exhaust gases, maximizing the velocity, and therefore, the thrust. The specific shape of the nozzle is designed to efficiently convert the high-pressure, high-temperature gas into high-velocity exhaust.
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).