Analysis of self-excited transverse combustion instability in a rectangular model rocket combustor
Analysis of self-excited transverse combustion instability in a rectangular model rocket combustor
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DOI：
10.1063/5.0086226
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发表时间：
2022-04
影响因子：
4.6
通讯作者：
Kangkang Guo;Yongjie Ren;Yiheng Tong;Wei Lin;W. Nie
中科院分区：
文献类型：
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作者：
Kangkang Guo;Yongjie Ren;Yiheng Tong;Wei Lin;W. Nie
甲烷/氧气混合物由于其实用性和低成本而被认为是许多未来火箭发动机的合适推进剂。为了更好地理解甲烷/氧气火箭发动机的燃烧不稳定性，对矩形多段燃烧室（RMC）内的横向自发燃烧不稳定性进行了实验和数值分析。在可重复的热火试验中，RMC发生了严重的燃烧不稳定性。基于应力混合涡模拟和火焰生成歧管方法，结合详细的化学反应机理（GRI Mech 3.0），通过数值模拟系统地研究了燃烧的物理机制。频谱和空间模式的数值计算结果与理论分析和实验数据吻合较好。通过瑞利指数分析，确定了燃烧室两侧燃烧不稳定性的驱动区域。氧化剂柱中的纵向压力振荡与燃烧室中的横向压力波耦合，导致推进剂质量流量的周期性振荡。此外，当压力波与燃烧室的壁相互作用时，混合被高度增强。因此，热量突然释放。脉动放热增强了压力振荡。一个闭环系统的正反馈与周期性振荡的推进剂的质量流量，和突然的热释放，被认为是目前的燃烧不稳定。
A methane/oxygen mixture is considered to be an appropriate propellant for many future rocket engines due to its practicality and low cost. To better understand the combustion instability in methane/oxygen-fed rocket engines, the spontaneous transverse combustion instability in a rectangular multi-element combustor (RMC) was analyzed both experimentally and numerically. Severe combustion instabilities occurred in the RMC during repeatable hot-fire tests. The physical mechanisms were systematically investigated through numerical simulations based on the stress-blended eddy simulation and flamelet-generated manifolds method with detailed chemical mechanisms (GRI Mech 3.0). The numerical results for the frequency spectrum and spatial modes agree well with the theoretical analysis and experimental data. The driven regions of the combustion instability were identified on both sides of the combustion chamber through a Rayleigh index analysis. The longitudinal pressure oscillations in the oxidizer post were found to be coupled with the transverse pressure waves in the combustion chamber and led to periodic oscillations of the mass flow rate of propellant. Moreover, the mixing was highly enhanced when the pressure wave interacted with walls of the combustion chamber. Therefore, a sudden release of heat occurred. The pressure oscillations were enhanced by pulsated heat release. A closed-loop system with positive feedback associated with periodic oscillations mass flow rate of the propellant, and sudden heat release, was believed to account for the present combustion instability.