A structured approach to the design and testing of LOX/kerosene impinging-jet injectors

• A design methodology is proposed for impinging-jet injectors. • Two different LOX/kerosene injectors were designed and cold-flow tested. • Emphasis is placed on achieving uniform distribution across each element. • A 66s hot-fire test was conducted, exhibiting nominal performance. Liquid rocket engine injectors are complex components that significantly influence engine performance, combustion stability and manufacturing cost. They typically cycle through numerous iterations during development and achieving an injector design that successfully meets the target criteria often requires the application of prior experience, extensive simulation and testing, and ordinary trial and error. In an effort to reduce the heuristic nature of the process, this paper proposes a methodological approach to impinging-jet injector design for LOX/Kerosene engines. This structured approach considers the risks and limitations of early decisions, such as element and manifold types, and their downstream effects on the design process. As an illustration of the approach, the methodology is applied to the design of two different injectors with varying inputs for the same engine. Both of these injectors were manufactured and cold-flow tested to characterize fluid dynamic performance. Cold-flow tests were conducted with water as an analog to analyze the propellant distribution through each orifice and pressure drop. One injector was hot-fire tested in a technology demonstrator liquid rocket engine and performed nominally, with high c * efficiency and stable combustion. The application of this methodology ensures a more deterministic approach to the injector design process potentially reducing the time and cost of development.