Ablative rocket engines use a combustion process that erodes or ablates the material from the engine’s internal surfaces to produce thrust. Ablative rocket engines are often used in applications where simplicity and cost-effectiveness are priorities. The ablation process helps dissipate the heat generated during combustion, preventing damage to the engine. However, the erosion of the ablative material limits the engine’s operational lifetime. Specific details of the engine’s performance depend on the choice of ablative material and the design of the engine components.
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).