Visualization of Combustion Flowfield in Injector Nearfield

In order to study the gas-gas mixing and combustion mechanism deeply,gas-gas combustion flow field in a chamber with quartz windows was conducted utilizing gaseous oxygen and hydrogen as propellants.The flame structure near the exit of the coaxial injector,tri-coaxial injector and swirl injector were captured by high-speed photography and digital camera.The results show that the gas-gas combustion occurs mainly in the mixing shear layer and the combustion flame develops from the injector post tip.The tri-coaxial injector has two shear combustion surfaces.Compared with the shear injector,the swirl injector burns more intensely.When the swirl number is large enough,a stable combustion recirculation zone may be formed in the center.