一种V字型诱导面的爆震起爆方案研究

Investigation of detonation ignition scheme based on a V-shape induced surface

  • 摘要: 相比氢燃料,使用碳氢燃料组织爆震对起爆条件要求更高。若想在有限尺寸的燃烧室内完成碳氢燃料的释热,需要对燃烧室进行精细合理的设计。为满足碳氢燃料在高速飞行器发动机内快速释热的要求,本文提出了一种V字型诱导面诱导爆震起爆方案。该方案通过精细设计燃烧室诱导面,利用激波相互作用和激波组合,对进入燃烧室内的燃料进行压缩,实现燃料在有限尺寸燃烧室内成功起爆释热的目的。数值结果显示,在斜楔诱导面和钝化斜楔诱导面都未能组织爆震燃烧的情况下,V字型诱导面能成功组织爆震燃烧,并在有限空间内完成燃料释热。V字型诱导面流场的主要波系结构呈现“倒V”字型,在燃烧室对称面附近发生爆震燃烧,随着波系向两侧壁面延伸发展,燃烧模式变为激波诱导燃烧。波系强度表现为中间强两边弱,有效降低了因激波边界层干扰带来的波系不驻定的风险。通过改变V字型前缘半径比,可使前缘区域的波系干扰模式发生变化,从而影响和控制整个流场的流动特征。

     

    Abstract: The organization of detonation using hydrocarbon fuel imposes stricter requirements on the initiation condition compared to hydrogen fuel. To ensure complete heat release within a combustion chamber of limited size, a well-designed combustion chamber is essential. To address the demand for rapid energy release from hydrocarbon fuels in hypersonic vehicle engines, This study proposes a detonation initiation scheme based on a V-shape induced surface. This approach employs a careful design of the induced surface to utilize shock wave interactions and shock wave combinations, compressing the incoming fuel and facilitating successful initiation and heat release within the combustion chamber. Numerical simulations demonstrate that, while neither the wedge surface nor the passivated wedge surface can achieve detonation, the V-shape inducted surface effectively initiates detonation and completes fuel combustion in the limited space. The main wave system in the flow field exhibits an inverted V-shaped structure, with detonation occurring near the symmetry plane of the combustion chamber. As the wave system propagates toward the sidewalls, the combustion mode transitions to a shock-induced combustion. The wave intensity is stronger in the symmetry plane and weaker near the sidewalls, which helps mitigate the risk of instability caused by shock-boundary layer interactions. Moreover, by adjusting the radius ratio of the V-shape leading edge, the interaction mode of the wave system within the leading-edge region can be modified, enabling control of the flow characteristics of the entire flow field.

     

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