Simulated time-dependent data to estimate uncertainty in fluid flow measurements
Simulated time-dependent data to estimate uncertainty in fluid flow measurements
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DOI：
10.1016/j.nucengdes.2018.07.005
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发表时间：
2018-10-01
影响因子：
1.7
通讯作者：
Ruggles, Arthur
中科院分区：
文献类型：
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作者：
Herald, Matthew;Bingham, Zachary;Ruggles, Arthur
正电子发射粒子跟踪（PEPT）是一种新兴的测量技术，用于实验流体流动的拉格朗日数据收集。测量的性质将湍流的研究扩展到缺乏光学访问的应用。在这项工作中使用的模拟管流PEPT测量，以验证重建算法，并确定新的不确定性来源。模拟测量发生在直径为38 mm的管道中，平均流速为0.55 m/s，雷诺数等于21，000。使用计算流体动力学（CFD）模拟流动，从CFD产生1000个随时间变化的示踪剂轨迹，以规定40 μ Ci氟-18点源的运动。Geant 4断层扫描发射应用程序（GATE）模拟Inveon临床前扫描仪模型的响应，并为规定的源生成一系列符合线。该阵列被提供给多个PEPT（mPEPT）代码，该代码重构模拟示踪剂的位置，并将位置分配给相干轨迹。将mPEPT重建轨迹与规定位置进行比较。使用2.0 ms时间步长，在所有方向上以0.0 mm为中心的测量偏差以及x、y和z分量中分别为0.29 mm、0.29 mm和0.30 mm的标准偏差，实现了754个轨迹的重建。识别了两个由测量体积中的两个示踪剂的接近引起的位置错配的实例。这是一个新的重建误差PEPT测量，无法识别没有这些模拟工具提供的示踪剂轨迹的先验知识。
Positron Emission Particle Tracking (PEPT) is an emerging measurement technique for Lagrangian data collection in experimental fluid flows. The nature of the measurement extends the study of turbulent flows to applications lacking optical access. A simulated pipe flow PEPT measurement is used in this work to verify reconstruction algorithm and identify novel sources of uncertainty. Simulated measurement occurs in a 38 mm diameter pipe with 0.55 m/s mean flow velocity and Reynolds number equal 21,000. Flow is simulated using computational fluid dynamics (CFD), generating 1000 time-dependent trajectories of tracers from CFD to prescribe movements of 40 mu Ci, fluorine-18-point sources. Geant4 Application for Tomographic Emission (GATE) simulates the response of the Inveon Pre-Clinical scanner model and produces an array of coincidence lines for the prescribed sources. The array is provided to a multiple PEPT (mPEPT) code reconstructing the position of simulated tracers and assigns positions to coherent trajectories. The mPEPT reconstructed trajectories are compared to prescribed positions. Reconstruction of 754 trajectories is achieved with measurement bias centered at 0.0 mm in all directions and standard deviation of 0.29 mm, 0.29 mm, and 0.30 mm in the x, y, and z component respectively using 2.0 ms time-steps. Two instances of position misassignments induced by the close-approach of two tracers in measurement volume are identified. This is a novel reconstruction error to PEPT measurements, unable to be identified without prior knowledge of tracer trajectories provided by these simulation tools.