Large eddy simulations of unsteady non-reaction flow characteristics using different geometrical combustor models

Large eddy simulations and power spectral density methods are used to investigate the unsteady non-reaction flow characteristics, as an important phenomenon in the combustor. The simulated was consistent with experimental velocity components and verified the effectiveness of this method. In the present work, four different geometric models of the combustion chamber were tested to assess the effects of primary holes and dilution holes on the contributions of unsteady features. The results reveal that vortex structures and pressure oscillations in turbulent field are enhanced because the primary and dilution holes exist. The dominant mechanisms that drive the non-unsteady instability are attributed to the formation of large-scale vortex structures. The oscillation amplitudes are affected by the primary and dilution holes. When the primary and dilution holes is eliminated from the combustor, the pressure oscillation amplitudes decrease. The research results are beneficial to further understand the unsteady non-reaction flow characteristics of geometrical combustors.