UCLA

Injector design has a significant impact on liquid rocket engine performance because it governs the atomization and mixing of propellants to produce stable combustion over a characteristic length scale. Additive manufacturing (AM) with high-performance metal alloys is revolutionizing combustion device design and development, particularly related to propellant injection. AM injectors can dramatically reduce part counts and implement complex fluid passageways that decrease injector forward pressure-drop, increase combustion stability, and enhance propellant mixing, thereby enabling improved rocket combustor performance and extending mission capabilities. This dissertation focuses on three subtopics of AM injector (coaxial and impinging) design and performance: (1) hydraulics, (2) propellant mixing, and (3) combustion instabilities. A combination of computational and experimental efforts are utilized, which include but are not limited to injector design, fluid dynamics analysis, and experimental hydraulics (cold-flow) and mixing/combustion studies using optical diagnostic techniques. Compiled results demonstrate the promising potential to leverage the flexibility of additive manufacturing to design advanced injector geometries that improve performance and reliability of liquid rocket engines.