Abstract: In order to find the effects of combustion mode transition on scramjet operating characteristics， a direct-connect experiment of combustion mode transition， which realized using linear change of liquid kerosene mass flow rate， was carried out. The inlet flow conditions of isolator accord with the flight Mach number 4.5 in this experiment. Based on monitoring of typical parameters in the characteristic position， the combustion mode could be distinguished in real time， and the influence law of combustion mode transition on scramjet performance was also achieved. Results show that parameter catastrophe includes wall pressure and thrust performance occurred during the mode transition process， and hysteresis phenomenon was obvious. When the flow rate of kerosene increases and decreases at the same rate， the equivalence ratio was different at the time of mode transition， and the ratio was 0.55 and 0.488， respectively. At equivalence ratio 0.488， results show 8.05% lower in combustor specific thrust than that of equivalence ratio 0.55. There was a different combustion mode for the same equivalence ratio in the hysteresis interval， corresponding to different thrust performance of scramjet engine.

Key words: Scramjet；Combustion mode；Transition；Direct connect；Experiment

摘要： 为获得燃烧模态转换过程对超燃冲压发动机工作特性的影响，在直连式实验台上，通过液态煤油流量的线性变化，开展了飞行马赫数4.5条件下燃烧室不同工作模态的转换实验。通过对特征位置和参数的监测，实现了燃烧模态的实时判别，获得了燃烧模态转换过程对发动机性能的影响规律。实验结果表明，在燃烧模态转换过程中滞环现象明显，燃烧室压力和发动机推力性能存在突变。在燃油流量以相同的速率增加和减小过程中发生模态转换时刻的燃油当量比存在差异，分别为0.55和0.488，两个转换点燃烧室比推相差8.05%。在滞环区间内，对于同一当量比，会存在两个不同燃烧模态，对应不同的发动机推力性能。

关键词: 超燃冲压发动机；燃烧模态；转换；直连式；实验