Pressure-fed rocket engines rely on the pressure of stored gases to force propellants into the combustion chamber. They are often used in smaller rockets and spacecraft. Specific details, such as the heating value of the propellant, mass flow rates, and mixture ratio values, would need to be obtained from engine performance data or technical specifications for the specific pressure-fed rocket engine being considered.
The propulsive efficiency is a crucial parameter in evaluating the performance of a rocket engine, indicating how well it converts propellant energy into useful thrust. Practical rocket engines often have propulsive efficiencies less than 100% due to factors like incomplete combustion, heat losses, and other inefficiencies in the propulsion system.
The propulsive efficiency () is defined by the following formula:
where,
- is the propulsive efficiency,
- is the thrust produced by the rocket engine,
- is the effective exhaust velocity of the rocket,
- ṁp is the mass flow rate of the propellants,
- is the specific impulse of the rocket engine,
- g0 is the acceleration due to gravity (approximately 9.81 m/s²).