In order to improve the performance of traditional ramjet, a ramjet based on pulse detonation (PD-Ramjet) instead of isobaric combustion was proposed. Several special-shaped detonation chambers which retained the characteristic structures of the dual-mode scramjet combustor were designed. Characteristic structures included the expansion channel and the cavity. The filling process and detonation initiation process of the stoichiometric hydrogen/air mixture under the incoming flow condition of the sub-combustion mode were studied in the detonation chambers with characteristic structures by two-dimensional numerical simulation method, and the influences of the characteristic structures on the filling process and detonation initiation process were analyzed. The simulation and analysis results indicated that the hydrogen concentration at both sides of the chamber near the outlet was low due to the structure of the expansion channel, and the pressure and velocity of the detonation wave decreased gradually after the expansion channel. The cavity had a significant influence on the filling process, which resulted in the uneven hydrogen concentration downstream the cavity, especially near the outlet of the chamber. The intensity of the detonation wave attenuated to a certain extent by reason of the cavity, where the peak pressure first decayed due to the sudden expansion of the flow path and then rose owing to the reflection at the cavity aft wall.

为了提高传统冲压式喷气发动机的性能，提出了一种基于脉冲爆震的冲压式喷气发动机（PD-Ramjet）替代等压燃烧。设计了几个保留了双模超燃冲压发动机燃烧室特征结构的异形爆震室。特征结构包括膨胀通道和空腔。采用二维数值模拟方法，在具有特征结构的爆轰室内研究了化学计量氢气/空气混合物在亚燃烧模式来流条件下的充填过程和起爆过程，并研究了特征结构对爆轰过程的影响。分析了填充过程和起爆过程。模拟分析结果表明，由于膨胀通道的结构，腔室两侧靠近出口的氢气浓度较低，膨胀通道后爆震波的压力和速度逐渐降低。空腔对充填过程有显着影响，导致空腔下游氢气浓度不均匀，特别是在腔室出口附近。爆轰波的强度因空腔而有所衰减，其峰值压力先因流道的突然扩大而衰减，然后因空腔后壁的反射而上升。膨胀通道后，爆震波的压力和速度逐渐降低。空腔对充填过程有显着影响，导致空腔下游氢气浓度不均匀，特别是在腔室出口附近。爆轰波的强度因空腔而有所衰减，其峰值压力先因流道的突然扩大而衰减，然后因空腔后壁的反射而上升。膨胀通道后，爆震波的压力和速度逐渐降低。空腔对充填过程有显着影响，导致空腔下游氢气浓度不均匀，特别是在腔室出口附近。爆轰波的强度因空腔而有所衰减，其峰值压力先因流道的突然扩大而衰减，然后因空腔后壁的反射而上升。