Very-large eddy simulation of hydrogen flames in strut-based supersonic combustor

The very-large eddy simulation (VLES) method was used to simulate the supersonic flames in the strut-injection hydrogen combustor of Germany’s Aerospace Centre (DLR), and the flame stabilization mechanism was analyzed by the conservative representation of chemical explosive mode analysis (CCEMA) method. The VLES turbulent model based on the k-ω shear stress transport (SST) model and the hybrid turbulent combustion model based on the Ingenito supersonic combustion model (ISCM) along with the partially stirred reactor (PaSR) model were adopted in this study. The time-averaged temperature and streamwise velocity profiles predicted by the numerical methods were in good agreement with the experiment. In terms of discretization method, a modified low dissipation shock-capturing scheme with better shock-capturing ability was proposed. Compared with the original scheme, the simulation fidelity of turbulence/flame structures in the ignition zone was further improved by the modified shock-capturing scheme. The flame diagnostic also showed that the component diffusion, chemical reaction and shock compression effects played positive roles in promoting the explosion mode before the flame onset location. In addition, the thermal explosion effect was more intensive than the radical explosion, indicating that the flame stability mode in the DLR combustor is a diffusion and compression effects assisted-ignition mode.