Abstract Metal particles in solid propellants enhance rocket engines performance. An interaction of particles with a high Reynolds number turbulent gas flow accelerating to a nozzle, has not been characterized thoroughly. We study the particle-turbulence interactions in a two-dimensional model of a rocket engine. Two-phase particle image/tracking velocimetry provides the flow velocity simultaneously with the velocities of irregularly shaped inertial particles (dp ~ 320 µm, Stokes St ~ 70, particle Reynolds number Rep ~ 300). We reveal the local augmentation of turbulent fluctuations in the particle wakes (up to 5 particle diameters downstream the particle). Despite the low mass fraction, the large response time of the particles leads to an increase of turbulent kinetic energy (TKE) everywhere in the chamber. The increase of local particle mass fraction near the nozzle, due to the mass conservation and converging streamlines, compensates for the dampening effect of the strong mean flow acceleration and further augments TKE at the nozzle inlet. Furthermore, this is accompanied by unexpectedly isotropic fluctuations in the proximity of the nozzle. The phenomenon of the isotropic, strongly enhanced turbulence in the proximity of the engine nozzle achievable with the low mass fraction of high St, Rep particles, can be used to improve the design of solid propellant rocket engines.

中文翻译：

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加速流中高斯托克斯数不规则形状粒子的粒子-湍流相互作用：火箭发动机模型

摘要 固体推进剂中的金属颗粒增强了火箭发动机的性能。粒子与加速到喷嘴的高雷诺数湍流气流的相互作用尚未完全表征。我们研究了火箭发动机二维模型中的粒子-湍流相互作用。两相粒子图像/跟踪测速仪同时提供流速和不规则形状惯性粒子的速度 (dp ~ 320 µm, Stokes St ~ 70, 粒子雷诺数 Rep ~ 300)。我们揭示了粒子尾流中湍流波动的局部增强（粒子下游高达 5 个粒子直径）。尽管质量分数低，但颗粒的大响应时间会导致腔室中各处的湍流动能 (TKE) 增加。由于质量守恒和收敛流线，喷嘴附近局部粒子质量分数的增加补偿了强平均流加速度的阻尼效应，并进一步增加了喷嘴入口处的 TKE。此外，这伴随着喷嘴附近出乎意料的各向同性波动。发动机喷嘴附近的各向同性、强烈增强的湍流现象可通过高 St、Rep 粒子的低质量分数实现，可用于改进固体推进剂火箭发动机的设计。这伴随着喷嘴附近出乎意料的各向同性波动。发动机喷嘴附近的各向同性、强烈增强的湍流现象可通过高 St、Rep 粒子的低质量分数实现，可用于改进固体推进剂火箭发动机的设计。这伴随着喷嘴附近出乎意料的各向同性波动。发动机喷嘴附近的各向同性、强烈增强的湍流现象可通过高 St、Rep 粒子的低质量分数实现，可用于改进固体推进剂火箭发动机的设计。