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首页> 外文学位 >Development of an ultra-high speed dynamic witness-plate particle image velocimeter for micro-detonator studies.
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Development of an ultra-high speed dynamic witness-plate particle image velocimeter for micro-detonator studies.

机译：开发用于微雷管研究的超高速动态见证板颗粒图像测速仪。

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摘要

An ultra-high speed particle image velocimetry (PIV) system is developed for measuring flow properties behind shock waves created by explosive detonators. Unique challenges are faced in extending the PIV technique to explosive output, including imaging in the presence of broadband explosive emission, nanosecond temporal resolution, and micro-scale spatial resolution. The outputs of explosive detonators are driven into dynamic witness plates, and time-resolved two-dimensional velocity-field measurements are made using the PIV system. The measurements represent the highest frame-rate PIV experiments ever performed and provide data describing the spatial profile of velocity in any direction within the experimental field-of-view.;As for the sub-microsecond properties of the flow behind detonator-induced shocks, the flow is unique in that the shock front acts as a flow boundary that moves much faster than the material flow itself, creating rapid time evolution that cannot be ignored in the PIV measurements. Further, the very small curvature of the moving shock, coupled with the change in density across it, acts like a strong, rapidly-changing lens that severely distorts the images of particles inside the shock and creates false motion of the images. These effects are analyzed and methods are developed to account for them in the experiments.;In the analysis, a Lagrangian model of the particle displacements in response to a moving shock provides the relationship between the measured displacement field and the true velocity field for the case of double-exposure PIV. It also suggests the possibility of measuring the velocity field using a single exposure and knowledge of the temporal evolution of the shock position. A dynamic mapping function between the object and image plane is developed to account for the additional light refraction at the shock-front boundary and is validated for a static case. The fact that the mapping function is dynamic leads to an interesting new equation relating the image displacements to the Eulerian velocity.;Application of the PIV system to exploding bridge wire output is demonstrated.
机译：开发了一种超高速粒子图像测速（PIV）系统，用于测量爆炸雷管产生的冲击波背后的流动特性。将PIV技术扩展到爆炸物输出面临着独特的挑战，包括在存在宽带爆炸物发射时成像，纳秒级时间分辨率和微尺度空间分辨率。炸药雷管的输出被驱动到动态见证板上，并使用PIV系统进行时间分辨的二维速度场测量。这些测量结果代表了有史以来最高的帧速率PIV实验，并提供了描述实验视野内任何方向上速度的空间分布的数据。流动的独特之处在于，冲击波前部作为流动边界比物质流本身移动得快得多，从而产生了快速的时间演化，这在PIV测量中无法忽略。此外，运动冲击的很小的曲率，加上其上密度的变化，就像一个结实的，快速更换的镜头，会严重扭曲冲击内部颗粒的图像，并产生虚假的运动。在实验中分析了这些影响并开发了解决这些问题的方法。在分析中，拉格朗日模型对运动冲击的响应是位移的拉格朗日模型，提供了该情况下实测位移场与真实速度场之间的关系双曝光PIV。它还暗示了使用单次曝光和对冲击位置的时间演变的了解来测量速度场的可能性。开发了对象与图像平面之间的动态映射功能，以解决在激波前边界处的附加光折射，并针对静态情况进行了验证。映射函数是动态的这一事实导致了一个有趣的新方程，该方程将图像位移与欧拉速度相关联。；演示了PIV系统在爆炸桥线输出中的应用。

著录项

  • 作者

    Murphy, Michael John.;

  • 作者单位

    Arizona State University.;

  • 授予单位 Arizona State University.;
  • 学科 Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 244 p.
  • 总页数 244
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 机械、仪表工业;
  • 关键词

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