膨胀波对斜劈稳定斜爆震波特性影响的数值研究

Numerical Study on Effects of Expansion Wave on Wedge-Stabilized Oblique Detonation Wave

关键词:  燃烧室  斜爆震波  有限长斜劈  膨胀波  解耦

Key words:  Combustor  Oblique detonation wave  Finite wedge  Expansion wave  Decoupling

摘要:

为探究燃烧室内可能存在的膨胀波对斜爆震稳定燃烧的影响，基于块结构自适应网格加密的AMROC程序，求解多组分可压缩化学反应流Euler方程，研究了膨胀波对斜劈诱导斜爆震流场的影响。发现无限长斜劈模型中，斜爆震波面角度是缓慢增加的，膨胀波影响下，斜爆震波面角度明显下降。从爆震波面角度变化中可以明显看出膨胀波的影响范围和爆震波的衰减程度。来流的低静压不会改变膨胀波影响范围，但容易导致爆震波衰减直至发生解耦，因此高马赫数低静压来流条件下斜爆震燃烧的稳定性和燃烧效率需要着重考虑。此外，使用普朗特-梅耶膨胀波基本原理对膨胀区进行分析，发现爆燃区流场参数与理论值吻合较好，且壁面附近前马赫线角度与近似膨胀波前沿较为接近；基于此，发展了一种定性评估斜劈末端膨胀波影响范围的手段，在膨胀波前马赫线角度基础上适当增加4°~10°，可以近似得到膨胀波的前沿位置。

Abstract:

In order to explore the effects of possible expansion waves in the combustor on the stable combustion of oblique detonation， based on the AMROC code with adaptive mesh refinement， the multi-component compressible reactive Euler equation was solved， and the effects of expansion wave on oblique detonation wave（ODW） induced by wedge were studied. It is found that in the case of infinite wedge， the angle of ODW increases slowly， and under the influence of expansion wave， the angle decreases significantly. The influence range of expansion wave and the attenuation degree of ODW can be clearly found in the figures of wave angle. The low static pressure of the inflow will not change the influence range of the expansion wave， but probably cause the attenuation of ODW until decoupling. Therefore， the stability and combustion efficiency of oblique detonation under the condition of high Mach number and low static pressure flow should be considered. In addition， Prandtl-Meyer expansion wave was used to analyze the expansion zone， and it is found that the flow field in the deflagration zone is in good agreement with the theoretical value， and the angle of forward Mach line near the wall is close to the angle of approximate expansion wave. Based on this， a qualitative evaluation method for the influence range of expansion wave at the end of wedge was developed. The front of expansion wave can be approximately obtained by adding 4°~10° to the angle of forward Mach line， which probably can be referred in the design of finite ODW combustor considering the influence of expansion wave.