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Acta Aeronautica et Astronautica Sinica ›› 2025, Vol. 46 ›› Issue (9): 231167.doi: 10.7527/S1000-6893.2024.31167

• Fluid Mechanics and Flight Mechanics • Previous Articles    

Experimental initiation process of oblique detonation wave in combustion chamber under high Mach number conditions

Xiaoyuan ZHANG1, Jinping LI1(), Hu MA2, Shizhong ZHANG1, Shuo CHEN2, Xingyu LU1   

  1. 1.State Key Laboratory of High Temperature Gas Dynamics,Institute of Mechanics,Chinese Academy of Sciences Beijing 100190,China
    2.School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China
  • Received:2024-09-09 Revised:2024-09-27 Accepted:2024-10-24 Online:2024-11-04 Published:2024-11-04
  • Contact: Jinping LI E-mail:lijinping@imech.ac.cn
  • Supported by:
    National Natural Science Foundation of China(11902328);Foundation of President of the Chinese Academy of Sciences(1702)

Abstract:

Oblique detonation technology offers significant advantages such as a simple structure, high combustion efficiency, and high specific impulse. However, limitations in ground-based experimental capabilities have hindered a deeper understanding of oblique detonation and the development of this technology. Based on a reverse detonation-driven shock tunnel directly connected system, this paper simulated a flight altitude of 30 km and a Mach number of 9 to make an experimental investigation of the initiation of oblique detonation waves with a wedge angle of 25° using ethylene fuel. The experimental system generates high-temperature and high-pressure air through a shock tube, which is then accelerated through a nozzle into the combustion chamber. Once the air flow field was established, fuel was injected and mixed with the air to initiate detonation. The structural characteristics and initiation process of the oblique detonation waves were observed and analyzed. Formation of a clear oblique detonation wave structure was found at the wedge. The features such as oblique shock waves, oblique detonation waves, transverse waves, and triple points were accurately identified. The high-brightness area behind the wave indicated intense chemical reactions. The oblique detonation wave remained stable for approximately 6 milliseconds, with the angle maintained within the range of 80°±2°. The experiments showed good repeatability. Analysis revealed that the experimentally obtained oblique detonation wave falls within the overdriven strong solution region of the extreme curve. The experiment detailed the initiation process of the oblique detonation wave. Before fuel injection, a stable oblique shock wave first formed at the front of the wedge. After fuel injection, the intersection of the oblique shock wave and the separation shock wave triggered the initiation of the mixed gas. The detonation wavefront formed after initiation was sustained by chemical reactions, gradually propagating forward with its length continuously increasing until reaching a stable state. Finally, the high pressure generated by the reflected shock wave in the shock tube disrupted the oblique detonation wave structure.

Key words: oblique detonation, shock, detonation initiation, wave structure, shock tunnel

CLC Number: