Many investigations of detonation-based combustors have identified reactant mixture inhomogeneity as having a leading-order impact on wave dynamics and combustion efficiency. To examine this phenomenon in a simplified context, an array of two- and three-dimensional channel detonation simulations are conducted in the present work. The reactant mixture consists of stratified fuel and air, wherein the randomly distributed equivalence ratio field features a characteristic stratification length scale. Detailed chemical kinetics are implemented in an adaptive mesh refinement solution framework where the region near the shock front is resolved with cells per representative ZND induction length. The results show that in comparison to baseline cases with uniform reactant mixtures, reactant stratification has a marked impact on the detonation structure. Increasing the stratification length scale increases the size and irregularity of the detonation cells, yielding larger variations in wave speed. Triple point collisions in fuel-rich regions lead to local wave speeds above the notional mean CJ speed, but wave passage through inert regions causes the local wave speed and strength to diminish. Conditional statistics show that increasing the stratification length scale increases the variance in pressure and temperature in the primary reaction zone, as well as the variance in heat release over a range of mixture conditions. In addition to the reactant mixture, the impact of the boundary condition behind the detonation is also investigated. The results show that an inflow boundary condition acts to over-drive the wave, leading to higher peak pressures, smaller detonation cells, and increased reactant consumption. On the other hand, cases with a wall behind the wave exhibit weaker waves with lower peak pressures and heat release rates, as well as greater variance in conditional quantities. Comparisons between complementary two- and three-dimensional simulations show reasonable qualitative agreement in wave structure, speed, and conditional statistics.

中文翻译：

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使用反应解析模拟在混合物分层存在的情况下的爆炸结构

对基于爆震的燃烧器的许多研究已经确定反应物混合物的不均匀性对波动力学和燃烧效率具有前序影响。为了在简化的背景下研究这种现象，本工作中进行了一系列二维和三维通道爆炸模拟。反应混合物由分层的燃料和空气组成，其中随机分布的当量比场具有特征分层长度尺度。详细的化学动力学在自适应网格细化解决方案框架中实现，其中冲击锋附近的区域用每个代表性 ZND 感应长度的单元来解析。结果表明，与具有均匀反应物混合物的基线情况相比，反应物分层对爆炸结构有显着影响。增加分层长度尺度会增加爆轰单元的尺寸和不规则性，从而产生更大的波速变化。富含燃料区域的三相点碰撞导致局部波速高于名义平均 CJ 速度，但波穿过惰性区域会导致局部波速和强度减小。条件统计表明，增加分层长度规模会增加主反应区压力和温度的变化，以及一系列混合条件下放热的变化。除了反应混合物之外，还研究了爆炸背后边界条件的影响。结果表明，流入边界条件会过度驱动波，导致更高的峰值压力、更小的爆震单元以及增加的反应物消耗。另一方面，波后面有墙的情况会表现出较弱的波，具有较低的峰值压力和放热率，以及条件量的较大方差。互补的二维和三维模拟之间的比较表明，在波浪结构、速度和条件统计方面具有合理的定性一致性。