共查询到18条相似文献,搜索用时 625 毫秒
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基于多参数耦合的S弯隐身喷管设计方法研究 总被引:4,自引:0,他引:4
《工程热物理学报》2015,(11)
本文详细介绍了一种基于多参数耦合的变截面S弯隐身喷管设计方法,所设计的喷管可实现对高温涡轮部件的完全遮挡。针对所设计的双S弯喷管,采用CFD技术对喷管流场进行了数值模拟,计算结果表明:双S弯喷管沿程截面Ma数分布存在明显的不均匀性;在喷管的第一弯转弯背风区及第二弯转弯背风区存在局部高速区域;虽然气流在S弯通道内经过了2道转弯,但在喷管内部未见分离现象;双S弯喷管在两个转弯处附近存在明显的总压损失。 相似文献
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Jason R. Burr 《Proceedings of the Combustion Institute》2019,37(3):3471-3478
An experimental study was conducted to characterize fundamental behavior of detonation waves propagating across an array of reactant jets inside a narrow channel, which simulated an unwrapped rotating detonation engine (RDE) configuration. Several key flow features in an ethylene-oxygen combustor were explored by sending detonation waves across reactant jets entering into cold bounding gas as well as hot combustion products. In this setup, ethylene and oxygen were injected separately into each recessed injector tube, while a total of 15 injectors were used to establish a partially premixed reactant jet array. The results revealed various details of transient flowfield, including a complex detonation wave front leading a curved oblique shock wave, the unsteady production of transverse waves at the edge of the reactant jets, and the onset of suppressed reactant jets re-entering the combustor following a detonation wave passage. The visualization images showed a complex, multidimensional, and highly irregular detonation wave front. It appeared non-uniform mixing of reactant jets lead to dynamic transverse wave structure. The refreshed reactant jets evolving in the wake of the detonation wave were severely distorted, indicating the effect of dynamic flowfield and rapid pressure change. The results suggest that the mixing between the fuel and oxidizer, as well as the mixing between the fresh reactants and the background products, should affect the stability of the RDE combustor processes. 相似文献
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Near-field flow and flame dynamics of LOX/methane shear-coaxial injector under supercritical conditions 总被引:2,自引:0,他引:2
The mixing and combustion of liquid oxygen (LOX) and gaseous methane of a shear coaxial injector operating under supercritical pressures have been numerically investigated. The near-field flow and flame dynamics are examined in depth, with emphasis placed on the flame-stabilization mechanisms. The model accommodates the full conservation laws and real-fluid thermodynamics and transport phenomena over the entire range of fluid states of concern. The injector flowfield is characterized by the evolution of the three mixing layers originating from the trailing edges of the two concentric tubes of the injector. As a consequence of the strong inertia of the oxygen stream and light density of methane, a diffusion-dominated flame is anchored in the wake of the LOX post and propagates downstream along the boundary of the oxygen stream. The large-scale vortices shedding from the outer rim of the LOX postengulf methane into the wake recirculation region to react with gasified oxygen. The frequencies of vortex shedding match closely those of the flow over a rear-facing step, mainly due to the large density disparity between LOX and gaseous methane. The effects of the momentum-flux ratio of the two streams are also examined. A higher-momentum methane stream enhances mixing and shortens the potential cores of both the LOX and methane jets. 相似文献
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为提高姿轨控液体火箭发动机同轴式喷注器掺混性能,设计了简化的双股矩形射流发生器,开展了等离子体控制射流实验,获得了射流流场结构与速度分布,结果表明与单股射流类似,双股矩形射流同样具有很好的相似性,随着射流速度差的增大,相似性进一步增强,混合点逐渐靠近射流发生器出口,混合角和混合率增大,而涡量最大值减小;等离子体对射流相似性的影响较弱,主要增大了发生器出口附近的速度,缩短了射流核心区长度,增大了射流宽度和混合角,使得混合点位置移向发生器出口,扩大了高涡量值区域范围,不过3种实验工况下射流涡量和的正、负值均比较接近,混合率也非常接近,并且随着射流速度差的增大,等离子体控制效果降低;总的来说,等离子体激励器应安装在低速射流中,增大混合角比控制混合点位置对提高混合率更有效. 相似文献
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气动光学的研究中,关联方程(linking equation)是关联湍流力学量与光学量的一个重要的方程.但是,基于模型简化的关联方程在亚声速低速流场的应用中通常忽略权重函数对波前方差估计精度的影响.本文在纳米粒子示踪平面激光散射技术获得超声速混合层流场密度数据的基础上,应用关联方程计算超声速混合层的流向波前方差,并进行误差分析.结果表明:基于关联方程估计的流向波前方差与直接对密度场的积分计算结果具有较好的一致性;在适当地定义相干长度、密度脉动协方差高斯模型近似的基础上,分析了权重函数对关联方程计算精度的影响,指出了权重函数对关联方程在超声速流场密度高度相关区域中应用的必要性.研究的开展对于拓展关联方程在高速流场中的应用具有一定指导意义. 相似文献
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采用计算流体力学方法,研究了以氮气为载气的新型高总压氧碘化学激光器(COIL)阵列喷管。模拟结果表明:采用高马赫数的氮气流引射低马赫数的氧气流,可以提高光腔出口的驻点压力;高超声速的氮气与声速的氧气混合较慢,在喷管出口安装翼片有利于增强气流混合;喷管出口安装大翼片,翼片诱导的横向涡可以到达氮喷管的中心,光腔内混合比较充分。通过采用10组分21反应的化学反应模型,模拟了阵列喷管内多组分气体的混合和化学反应过程。模拟结果表明:光腔内生成了激发态碘原子和基态碘原子,光腔中获得了正增益,而且光腔出口的总压也由2.6 kPa提升至28.9 kPa。 相似文献