Affiliations: 4-16-2-201 Nagamachiminami Taihaku-ku Sendai 982-0012,
Japan. | National Aerospace Laboratory, Kakuda Research Center,
Kakuda, Miyagi 981-1525, Japan. | Department of Mechanical Engineering, Kobe University,
Nada, Kobe 657-8501, Japan.
Abstract: The mixing fields within a SCRAM-jet combustion chamber are
visualized using pressure-sensitive paint (PSP) as an oxygen sensor. The
experiments are performed in a small supersonic wind tunnel at the National
Aerospace Laboratory - Kakuda Research Center (NAL-KRC). The main stream Mach
number is 2.4, and the dynamic pressure ratios between the injected gas and the
main flow are 0.3, 0.7, 1.1 and 1.5. Three fuel injection nozzles are used;
oxygen is injected from the central nozzle and air from the two nozzles at
either side. The spread of the injected gas is measured to observe the effects
of placing the nozzles in different positions. The results show that the jet
has its own independent flow structure, and that little mixing of gases occurs
between the flow structures created by each nozzle. When the injection dynamic
pressure ratio is increased, the oxygen fraction rises in the recirculation
zone and falls in the separation zone downstream of the injection.
