微小尺度多循环爆震实验研究

Experimental Research on Multi-Cycle De tonations at Micro Scale

关键词:  微小尺度  爆震  多循环  缓燃向爆震转变

Key words:  Micro-scale  Detonation  Multi-cycle  Deflagration to detonation transition

摘要:

为了探索爆震燃烧应用于微型推进器的可行性，进行了微小尺度多循环爆震实验的研究。实验管道采用截面为6mm×6mm，长度为500mm的方型爆震室，氧化剂和燃料分别为40%的富氧空气和乙烯，工作频率范围为1～30Hz。实验中采用高速摄影仪拍摄反应波的传播过程，用压力传感器测量反应波的压力变化。结果表明，工作频率在1～20Hz内时可以成功实现多循环爆震，爆震波离开爆震室的速度约为2500m/s，频率越高，缓燃向爆震转变(Deflagration to Detonation Transition，简称DDT)的距离越长；工作频率为10Hz和20Hz时，同一频率下，不同爆震循环的DDT开始位置不同，并且DDT距离也存在差异；工作频率为25Hz和30Hz时，由于混合气填充量的减小，不能形成爆震。

Abstract:

To investigate the feasibility of the application of detonation combustion in micro-thruster， experiments were carried out on multi-cycle detonations at micro scale. The micro detonation chamber is 500mm in length with a 6mm×6mm rectangular cross-section. Oxygen-enriched air (40% by volume) and ethylene were used as oxidizer and fuel， and the operating frequencies ranged from 1 to 30Hz. High-speed camera was used to capture the propagation process of the reaction waves， whose pressures were measured by piezoelectric transducers. The results showed that， when the operation frequency ranging from 1 to 20Hz， multi-cycle detonation could be successfully obtained， and the detonation waves propagated at approximately 2500m/s before reaching the chamber exit. And the higher the frequency， the longer the DDT distanceis. When operated at 10Hz and 20Hz， both the DDT point and the DDT distance vary in different cycles at the same operation frequency. When the frequency was 25Hz and 30Hz， detonation failed to occur due to the insufficient gas filling and mixing.