Numerical study on the mixing enhancement induced by the interaction between the hydrogen/ air coaxial jets and oblique shock wave at Mach 3 supersonic crossflow

The comprehensive performance of the scramjet is greatly influenced by the supersonic fuel mixing process. In the research, the mixing properties of the combination between the hydrogen/air coaxial jets and oblique shock at Mach 3 supersonic crossflow are investigated. The focus of the investigation is to reveal the mixing enhancement mechanism of coaxial jets and the impact of oblique shock on the mixing process. The numerical simulation is based on three-dimensional compressible RANS equations combined with the SST k -u turbulence model. The hydrogen spatial distribution, flow features, vortex structure, penetration depth, stagnation pressure loss and mixing efficiency with different working conditions are evaluated and studied. Our computational results demonstrate that the coaxial jets enhance mixing through the intense shear action between the annular fuel jet with the inner and outer air layers, and the oblique shock contributes to the mixing process by strengthening the interaction between jet and airflow, improving fuel distribution and inducing streamwise vorticity. In addition, the hydrogen distribution and mixing properties are affected by the action position of the incident shock. According to the achieved results, the coaxial jets combined with the oblique shock impinging downstream of the jet have the highest mixing efficiency, which is improved by 63.27% compared to the reference case. (c) 2023 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.