环形通道内爆轰波的起爆机制  

Initiation Mechanism of Detonation Wave in an Annular Channel

作　　者：贺顺江 任会兰[1] 李健[1] HE Shunjiang;REN Huilan;LI Jian(State Key Laboratory of Explosion Science and Technology,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]北京理工大学爆炸科学与技术国家重点实验室,北京100081

出　　处：《高压物理学报》2023年第1期159-168,共10页Chinese Journal of High Pressure Physics

基　　金：国家自然科学基金(12072036)。

摘　　要：旋转爆轰发动机环形燃烧室和预爆轰管的设计是影响发动机点火性能的关键因素。为了获得环形燃烧室中的起爆机制,使用多帧短时开快门摄像法,研究了不同含量氩气稀释的乙炔-氧气爆轰波经直管道沿切向进入环形通道中的传播过程和模式,重点关注爆轰波的失效和重新起爆机制。通过分析胞格模式发现环形通道内爆轰波的传播模式可以分为亚临界、临界和超临界3种状态。环形通道内爆轰波在顺时针和逆时针方向同时传播,根据初始压力和环形管道宽度的不同,会出现完全熄爆模式、熄爆-重新起爆模式和完全不熄爆模式,对应亚临界、临界和超临界3种状态。3种状态在顺时针和逆时针方向出现的顺序并不一致,相比较而言逆时针方向更易熄爆。研究同时也发现重新起爆通过两种方式实现:一种是通过解耦爆轰波与内壁面的反射以及其后的横向爆轰波,另外一种是通过燃烧转爆轰。通过分析直管的临界管径发现,随着环形通道宽度的增大,对于高浓度或低浓度氩气稀释的乙炔-氧气爆轰波,其临界管径均趋近于经典衍射问题中不稳定爆轰波的临界管径。实验研究结论将为旋转爆轰发动机燃烧室和预爆轰管的结构设计提供技术支持。The design of annular combustion chamber and pre-detonation tube of rotary detonation engines is the key factor affecting the ignition performance of the engines.In order to obtain the detonation initiation mechanism in an annular combustion chamber,the multi-frame short-time shutter-opening method was used in experiment to study the propagation process and mode of the detonation wave of acetylene and oxygen with different argon dilutions entering an annular channel tangentially through a straight pipe.We focus on the mechanism of detonation wave failure and reinitiation.By analyzing the cellular mode,it is found that the propagation mode of the detonation wave in the annular channel can be divided into three states:subcritical,critical and supercritical.The detonation wave in the annular channel propagates clockwise and counterclockwise at the same time.Depending on the initial pressure and the width of the channel,there can be a mode of complete detonation,a mode of detonation-reignition,and a mode of no detonation at all,corresponding to subcritical,critical and supercritical states.The order in which the three states appear in the clockwise and counterclockwise directions are not consistent,and the counterclockwise propagation is more likely to be extinguished.The study also found that reinitiation is achieved in two ways.One is by decoupling the reflection of the detonation wave from the inner wall surface and the subsequent lateral detonation wave,and the other is by burning to detonation.By analyzing the critical tube diameter of the straight tube,it is found that the critical tube diameter approaches the unstable detonation in the classical diffraction problem as the width of the channel increases,regardless of whether the detonation wave of acetylene and oxygen is diluted by high concentration or low concentration of argon gas.The experimental results can provide technical support for the structural design of the combustion chamber and pre-detonation tube of rotary detonation engines.

关 键 词：旋转爆轰发动机 反射和衍射 重新起爆 胞格结构 

分 类 号：O382.1[理学—流体力学] V211.7[理学—力学]