Laboratory-Scale Preburner for Selectable Flow Conditions in ORSC Experiments

摘要

Interest in understanding the combustion behavior of gas-centered swirl coaxial injectors has led to a variety of experimental and computational efforts to measure combustion performance, combustion stability margins, and wall heating effects. A gaseous oxygen/gaseous hydrogen preburner capable of flow rates up to 3 Ibm/s and pressures up to 3000 psia chamber operation was designed and built to provide warm oxygen flow to a main chamber injector in oxygen-rich staged combustion devices. An injector was selected to provide high combustion efficiency while balancing characteristic length and physical envelope requirements. Low thermal conductivity materials and thermal barrier coatings were used to reduce heat loss to the preburner structure and deliver a consistent temperature to the main injector throughout the test duration. To isolate the preburner operation from main chamber dynamics as well as reduce the domain required in potential modeling efforts, a choked flow condition was maintained at the preburner exit into the main injector oxidizer manifold. A venturi-style throat was used to provide pressure recovery and reduce upstream feed system pressure requirements. Testing has shown the preburner to deliver flat and uniform temperature profiles at levels determined by varying the oxygen and hydrogen mixture ratio. The preburner injector has been throttled down to 20% with stable operation and mixture ratios as high as 600 have been effectively used.