Nuclear thermal rocket engines are a type of propulsion system that uses a nuclear reactor to heat a propellant (such as hydrogen) to generate thrust. The primary advantage of nuclear thermal propulsion is its potential for high specific impulse, allowing for more efficient space travel. However, control volume analysis, as traditionally used in fluid dynamics, may not be directly applicable to nuclear thermal rocket engines. Instead, the thrust can be explained using the basic principles of momentum conservation.
In a nuclear thermal rocket engine, the nuclear reactor heats a propellant to high temperatures, and the hot propellant is expelled at high velocity through a rocket nozzle, generating thrust through the principle of action and reaction.
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).