Power Cycle ComponentPreburnerby Various (staged combustion engines only)
Typical Specifications
Gas Temperature
500u2013800u00b0C
Pressure
20u201350 MPa (higher than main chamber)
Flow
100% of one propellant + partial second
Operating Principle
The preburner burns either all the fuel with some oxidizer (fuel-rich, as in RS-25) or all the oxidizer with some fuel (oxidizer-rich, as in RD-180). The resulting hot gas at 500–800°C drives the turbine, then enters the main chamber where the remaining propellant completes combustion.
A preburner is a combustion device used in staged combustion cycle engines that burns all of one propellant with a portion of the other to create hot, high-pressure gas that drives the turbopump. Unlike a gas generator, the preburner exhaust is fed into the main combustion chamber rather than dumped overboard, so all propellant contributes to thrust. This enables higher efficiency at the cost of greater complexity.
Materials
Used In Engines
Common Failure Modes
Metal ignition in oxygen-rich preburners, thermal fatigue, injector erosion, coking in fuel-rich preburners
Recent Innovations
Oxidizer-rich preburners (Russian innovation, RD-170 family), dual preburners in full-flow staged combustion (Raptor), advanced injector designs for uniform temperature
