Main Chamber Injectors for Advanced Hydrocarbon Booster Engines

Abstract

Achieving the highest possible specific impulse has long been a key driver for space launch systems. Recently, more importance has been placed on the need for increased reliability and streamlined launch operations. These general factors along. with more specific mission requirements have provIded a new focus that is centered on the oxidizer rich staged combustion (ORSC) cycle. Despite a history of use in Russia that extends back to the 1960's, a proven design methodology for ORSC cycle. engines does not exist in the West. This lack of design expertise extends to the main chamber injector, a critical. subcomponent that largely determines the engine performance and main chamber life .. The goals ~f. the effort described here are to establIsh an empmcal knowledge base to provide a fundamental understanding of main chamber injectors and for verification of an injector design methodology for the ORSC cycle. The design of a "baseline" injector element, derived from information on Russian engines in the open literature, is presented. The baseline injector comprises a gaseous oxidizer core flow and an annular swirling fuel flow. Sets of equations describing the steady-state and the dynamic characteristics of the injector are presented; these equations, which form the basis of the design analysis methodology, will be verified in tests later this year. On~going cold flow studies, using nitrogen and water as simulants, are described which indicate highly atomized and symmetric sprays.

Dynamic Characterization of Double Swirl Injectors for GOX/Kerosene

“…Based on the gas-jet injector type 4,5,6,7 , which is one of the most commonly used design configurations in hydrocarbon/oxygen staged combustion engines, it has been derived by means of scaling from the jet-swirl injector with internal mixing originally deployed in the 20 mm combustion chamber (refer to publications 1-3).…”

Spray and atomization characteristics of gas-centered swirl coaxial injectors

“…Recess plays a very important role in mixing and atomization process. The recess cavity also acts as an acoustic resonator to withdraw a significant part of the acoustic energy from the combustion chamber to the gas manifold, 8 thus controlling the pulsation due to pressure drop and self-oscillation. Recess region can also enhance the mixing efficiency and flame stability through internal mixing of propellants.…”