基于小尺寸模型分析氢氧旋转爆轰波传播的不稳定性机制OA北大核心

The high reactivity of hydrogen and oxygen poses a huge challenge to the stable propagation of rotating detonation waves.To study the propagation instability of hydrogen-oxygen rotating detonation waves,based on the RYrhoCentralFoam solver developed by OpenFOAM,numerical simulations were conducted on two-dimensional hydrogen-oxygen rotating detonation waves in small scale model by changing the equivalence ratio.The complex and variable propagation characteristics of hydrogen-oxygen rotating detonation waves were revealed,and the typical flow field was analyzed.The instability of propagation modes and the quenching and re-initiation mechanisms of detonation waves were explored.The results show that as the equivalence ratio increases,the flow field exhibits three propagation modes:extinction,single wave,and hybrid waves.The detonation wave velocity increases almost linearly with the increase of equivalence ratio,with a velocity deficit of 5％to 8％.The disturbance of shock waves causes significant distortion and wrinkling on the deflagration surface,while the high reactivity of hydrogen and oxygen results in obvious layering on the deflagration surface and different instability at the two interfaces.The upper interface exhibits Kelvin-Helmholtz(K-H)instability,while the lower interface exhibits Rayleigh-Taylor(R-T)instability.As for the hybrid waves,the detonation wave is extremely unstable,maintaining a cycle between three states:quenching,single wave,and double wave collision.There are two ways in which detonation waves can be extinguished:firstly,the collision of two waves leads to the quenching of the detonation wave,and secondly,the intensification of combustion on the deflagration surface leads to the downward movement of the deflagration surface,ultimately resulting in the quenching of the detonation wave.The main reason for re-initiation is that the R-T instability induces detonation products and fresh premixed gas squeezing each other on the deflagration surface.The interaction between fresh premixed gas and products produces spikes and bubbles,enhances the reaction heat release on the deflagration surface,and generates local hotspots.The hotspots gradually increase into detonation waves,achieving the transition from deflagration to detonation.