填充不均匀对环形通道内爆震波传播特性的影响数值研究

A numerical study was conducted to investigate the impact of non-uniform filling of fresh mixtures on the propagation characteristics of detonation waves in the annular rotating detonation combustor，aiming to establish the critical criteria for the transition of propagation modes. The C₂H₄/O₂/N₂ mixture was utilized while the incomplete filling gap（i），the initial pressure（p₀），and the dilution ratio（β）were varied to investigate the propagation of detonation waves in the annular channel with non-uniform filling of fresh mixtures. It was observed that an increase in the velocity deficit of the detonation wave was resulted as the increase in the incomplete filling gap，the decrease in the initial pressure，and the increase in the dilution ratio. Four propagation modes were obtained，i.e.，the stable mode，the weakly unstable mode，the highly unstable mode and the deflagration mode. For an annular channel with a fixed inner radius of 65 mm and a channel height（h）of 15 mm，the transition criteria of the propagation modes are as follows：when i<h-2.0λ_a（λ_a is average cell size），the velocity deficit at the inner wall is within 20%，indicating the stable mode. When h-2.0λ_a<i<h-1.0λ_a，the velocity deficit at the inner wall is within 20%~40%，indicating the weakly unstable mode；when h-1.0λ_a<i<h-0.6λ_a，the velocity deficit at the inner wall is above 40% but not developing into the deflagration，indicating the highly unstable mode；and when i>h-0.6λ_a，the detonation wave completely decouples and transits to the deflagration mode.