Abstract:
The mixing process plays an important role in supersonic combustion, and sufficient mixing between the incoming supersonic air and the fuel is closely related to the overall performance of the airbreathing hypersonic propulsion system. In the present study, vane vortex generators are placed in front of the injector to promote the mixing of the fuel and the air. The three-dimensional compressible N-S equations and the two-equation SST
k-
ω turbulence model are used to simulate the cold flow field of the hydrogen transverse jet in a scramjet combustor. Effects of the vane vortex generator height and length on the flow field structure, vorticity intensity, mixing characteristics of hydrogen/air and total pressure loss in the combustor have been investigated. The results show that the vane vortex generator can greatly improve the vorticity intensity and the mixing performance of the combustor. With the increase of the vortex generator height and length, the interaction among flow field structures increases, resulting in the increase of the vorticity intensity and penetration depth, thus improves the fuel mixing efficiency in the combustor. Compared to the scheme without vortex generators, the penetration depth of the hydrogen jet can be increased by more than 170%, and the distance of the complete mixing can be reduced by more than 70%. More complex flow field structures also increase the total pressure loss of the combustor, and this effect increases with the height and length of the vortex generator. Compared to the improvement of the mixing performance, the increase of the total pressure loss is much smaller, indicating that the vane vortex generator can effectively improve the mixing performance of the combustor through reasonable parameter selection.