爆轰波与激波对撞爆轰状态演化机理研究

INVESTIGATION INTO MECHANISMS UNDERLYING HEAD-ON COLLISION OF DETONATIONS WITH SHOCK WAVES

对当量比氢氧混合气体中爆轰波与激波的正面对撞过程进行了二维数值研究.采用了二阶精度NND差分格式与改进的两阶段化学反应模型,并以数值x-t纹影图以及烟迹图记录了对撞过程.数值研究表明,透射爆轰波受到膨胀影响首先会衰减,甚至产生局部解耦现象;然后由于三波点的碰撞又能再次重新耦合.在爆轰波对撞过程中,由于燃烧不均匀性而产生的弱横波对爆轰胞格的形成起着重要作用.

A 2D numerical study on head-on collision of detonation waves with shock waves of different strengths in the gaseous mixture of hydrogen and oxygen under equivalence-ratio state has been carried out. The NND scheme and chemical model with improved two-step reaction was used and the x-t streak schlieren diagrams and smoke foil photographics were numericMly recorded to study the collision process. It was found that the transmitted detonation wave is attenuated firstly and even partially decoupled due to expansion effect. However, the collision of triple points along the detonation front can induce re-coupling which may consequently restore the detonation. In the collision process, the weak transverse waves are generated by inhomogenous combustion in the near wake of the Mach stem. The repeated collision of weak transverse waves can form new cellular structures.