A Comparison of Fluidic and Physical Obstacles for Deflagration-to-Detonation Transition
A Comparison of Fluidic and Physical Obstacles for Deflagration-to-Detonation Transition
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DOI：
10.2514/6.2011-587
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发表时间：
2011-01
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影响因子：
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通讯作者：
Benjamin Knox;D. Forliti;C. A. Stevens;J. Hoke;F. Schauer
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文献类型：
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作者：
Benjamin Knox;D. Forliti;C. A. Stevens;J. Hoke;F. Schauer
摘要：已提出流体障碍作为脉冲爆震发动机（PDE）中使用的传统爆燃到爆震过渡（DDT）增强装置的替代品。利用不稳定的反应流和稳定的非反应流获得了实验结果，以深入了解流体障碍的相对性能。使用化学计量预混合氢气-空气，仅使用与物理孔板的 DDT 距离相当的流体障碍即可实现向爆炸的过渡。由于高速射流固有的强烈湍流混合特性以及虚拟障碍物产生的阻塞，实现了火焰加速。在非反应稳定流期间使用热膜风速测定法在两个障碍物下游进行的湍流强度 (T.I.) 测量显示出保守的趋势，即与物理障碍物相比，流体障碍物产生的湍流强度增加了约 240%。由于上游 T.I. 的增加，点火时间减少了约 45%。在 PDE 循环的填充部分期间相对于流体障碍的水平。对于预混合化学计量氢气-空气和纯空气的喷射组合物，获得了向爆炸的转变。
Abstract : A fluidic obstacle has been proposed as an alternative to conventional deflagration-to-detonation transition (DDT) enhancement devices for use in a Pulsed Detonation Engine (PDE). Experimental results have been obtained utilizing unsteady reacting and steady non-reacting flow to gain insight on the relative performance of a fluidic obstacle. Using stoichiometric premixed hydrogen-air, transition to detonation has been achieved using solely a fluidic obstacle with comparable DDT distances to that of a physical orifice plate. Flame acceleration is achieved due to the intense turbulent mixing characteristics inherent of a high-velocity jet and the blockage created by the virtual obstacle. Turbulence intensity (T.I.) measurements, taken downstream of both obstacles with hot-film anemometry during non-reacting steady flow, show a conservative trend that a fluidic obstacle produces approximately a 240% increase in turbulence intensity compared to that of a physical obstacle. Ignition times were reduced approximately 45%, attributable to the increase in upstream T.I. levels relative to the fluidic obstacle during the fill portion of the PDE's cycle. Transition to detonation was obtained for injection compositions of both premixed stoichiometric hydrogen-air and pure air.