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为研究贫燃条件下当量比对交流介质阻挡放电等离子体辅助起爆的影响,采用松耦合方法仿真求解了当量比分别为1.0,0.8及0.6三种条件下氢氧预混气体起爆过程,对比研究了放电产物时空分布特性、不同阶段爆震管内流场参数分布、起爆时间和距离以及推力壁动态历程。结果表明放电产物在同一周期内的时空分布形态不随当量比改变而变化,但随着当量比下降,各主要活性粒子的密度增大,增幅则降低。随着管内流速上升,等离子体对流场结构的改变更加明显,加速了形成稳定爆震波的各个子过程;不同工况下等离子体都缩短了起爆时间和距离,但当量比越低,缩短程度越小。对推力壁受力的动态分析也显示等离子体对流场演化的加速效果随当量比减小而减弱,不过其受力大小与等离子体无关。在本文贫燃条件下出现低当量比不利于等离子体发挥作用的原因包含两点,一是燃料占比降低带来的不利影响大于等离子体助燃的效果,二是放电区域尺寸有限。
In order to study the effect of equivalence ratio on the auxiliary detonation of AC plasma barrier discharge plasma under lean-burn conditions, the initiation process of hydrogen-oxygen premixed gas under equivalent conditions of 1.0, 0.8 and 0.6 respectively was simulated by the loose coupling method. The temporal and spatial distribution characteristics of discharge products, the distribution of the parameters of the flow field in the detonation tube at different stages, the detonation time and distance, and the dynamic history of the thrust wall were also discussed. The results show that the shape of the spatiotemporal distribution of the discharge products does not change with the equivalence ratio during the same period. However, with the equivalence ratio decreasing, the density of the major active particles increases and the increase decreases. With the increase of the velocity in the tube, the change of the structure of the plasma flow field becomes more obvious, which speeds up the formation of stable detonation waves. The plasma detonation time and distance are shortened under different working conditions. However, the lower the equivalence ratio, the shorter The smaller. The dynamic analysis of the thrust wall force also shows that the accelerating effect of the plasma on the evolution of the flow field is weakened with the decrease of the equivalence ratio, but its force is independent of the plasma. There are two reasons why the low equivalence ratio is not conducive to plasma in this lean burn condition. First, the adverse effect caused by the decrease of the proportion of fuel is larger than the effect of plasma combustion. Second, the size of the discharge area is limited.