Injector Stability Screening Technique (ISST)

ABSTRACT: ORBITEC proposes to demonstrate and validate a laboratory-scale experimental injector stability screening technique which will quantify injector element stability characteristics. The experimental approach promises to dramatically reduce development cost by utilizing a gaseous single element test facility which presents savings in hardware manufacturing, consumables, and test facility labor. The simple test facility will allow rapid stability characterization of multiple candidate injectors which will be unobtrusive to schedule requirements. The key cost and time savings will be fewer full-scale hardware configurations that must be manufactured which will in turn reduce the number of full-scale tests required for qualification. The Phase I effort evaluated a Russian pentad injector at full-scale and laboratory-scale conditions. Correlation between laboratory scale and full scale experimental data showed that both combustion devices operated without experiencing high frequency combustion instability. During Phase II, an available database for the injector will be utilized to ensure unstable operation which will be scaled up for engine testing. Laboratory-scale methods of providing similarity such as heating and reactant dilution will also be evaluated. The Phase II programs will set the necessary scaling requirements and produce plans for Phase III ORBITEC test facility implementation. BENEFIT: The end product of this overall research and validation effort will create an experimental test facility and scaling technique which will significantly decrease engine development time at a reduced cost. The scaling technique will have application to virtually all high pressure liquid rocket engine development programs and existing engine upgrades for the Air Force, Navy, MDA, NASA and their contractors as well as commercial satellite launch companies. Development may reveal application to the screech phenomenon in air-breathing engines which will significantly open the commercial aircraft sector.