// PROPULSION SYSTEMS AND ENGINE TECHNOLOGY TERM
Coaxial Injector
A coaxial injector is a device used in liquid rocket engines that sprays liquid fuel and oxidizer into the combustion chamber through concentric tubes, ensuring they mix well for efficient burning. One fluid flows through the inner tube, and the other flows through the outer tube around it.
TECHNICAL DEFINITION
A coaxial injector is a critical component in liquid propellant rocket engines, facilitating the efficient mixing and atomization of liquid propellants (typically fuel and oxidizer) by discharging them through concentric orifices into the combustion chamber, optimizing combustion stability and performance.
BACKGROUND
William Alfonso Sirignano is an American aerospace engineer and fluid dynamicist. He is known for his theoretical work on resolving combustion instability problems in the Rocketdyne F-1 engine during the Apollo program, for the widely used Abramzon–Sirignano droplet vaporization model, and for pioneering the turbine-burner concept in jet propulsion.
READ MORE ON WIKIPEDIASYNONYMS & ALIASES
- Concentric injector
- Coax injector
- Annular injector
- Liquid-liquid injector
USAGE NOTE
These injectors are widely employed in liquid rocket engines, particularly those using hypergolic or cryogenic propellants, to achieve stable combustion and high thrust efficiency.
DEVELOPERS
Organizations developing technology related to Coaxial Injector.
SpaceX designs, manufactures, and launches advanced rockets and spacecraft. Their Raptor engine, used in the Starship vehicle, utilizes highly efficient coaxial pintle injectors for methane-oxygen combustion.
Blue Origin is developing a variety of rocket engines, including the BE-4 for the Vulcan Centaur and New Glenn rockets. These liquid rocket engines leverage advanced injector designs, including coaxial types, for high-performance combustion of methane and oxygen.
Aerojet Rocketdyne is a premier designer and manufacturer of rocket engines and propulsion systems. They have extensive experience in developing and testing various injector technologies, including coaxial designs, for a wide range of propellants.
NASA, particularly centers like Marshall Space Flight Center and Glenn Research Center, conducts extensive research and development in advanced rocket propulsion, including fundamental studies and experimental testing of coaxial injectors for various propellant combinations like LOX/LH2 and LOX/methane.
ArianeGroup develops and supplies propulsion systems for the Ariane family of launchers. Their advanced engine programs involve research into optimized combustion and injector technologies, including coaxial designs, for efficient and reliable operation.
Relativity Space is known for 3D printing entire rockets. Their Aeon engines, designed for their Terran 1 and Terran R vehicles, incorporate additively manufactured engine components, including advanced coaxial injector designs for methane-oxygen propellants.
Isar Aerospace is a German New Space company developing launch vehicles. Their Aquila engine, which powers their Spectrum rocket, features high-performance liquid propellant combustion with advanced injector technology, likely including coaxial designs.
Launcher is developing high-performance liquid rocket engines, such as the Engine-2 (E-2), designed for efficiency and reusability. Their approach involves advanced injector designs, including coaxial elements, for optimal combustion of liquid oxygen and kerosene.