Numerical Study of Hydrogen-Fueled Scramjet Performance with Passive Techniques

Mixing and combustion efficiencies are two important parameters to visualize the performance of scramjet. The rate of combustion strongly depends on the rate of mixing of fuel and air; hence, the mixing efficiency of fuel and supersonic airstream is the major parameter to optimize the performance of scramjet combustor. In this research paper, the numerical investigation has been carried out to enhance the mixing efficiency of fuel and supersonic air by using passive techniques. The passive techniques are implemented to DLR scramjet by creating the wall attached fuel injectors at various locations and developed different computational geometries. Computational fluid dynamics tool ANSYS Fluent 15.0 has been used to solve the fluid flow governing equations and reaction mechanism of fuel and air along with finite rate/eddy dissipation reaction model. Shear stress transport k-ω turbulence model is used for turbulence modeling. Validation of results has been performed with the DLR experimental results available in the open literature and identified a good matching of numerical and experimental results. From the analysis and comparison of numerical results for different passive techniques, it has been noticed that more recirculation regions, oblique and expansion shock waves are developed with the wall attached fuel injectors along with strut injector. These are very much helpful to penetrate into fuel stream and increasing the fuel carrying capacity, which can increase the mixing of fuel and supersonic air.