Experiments in Fluids ( IF 2.3 ) Pub Date : 2021-05-05 , DOI: 10.1007/s00348-021-03207-6 D Shekhtman 1 , W M Yu 2 , M A Mustafa 1 , N J Parziale 1 , J M Austin 2
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Abstract
We apply Krypton Tagging Velocimetry (KTV) to measure velocity profiles in the freestream of a large, national-scale high-enthalpy facility, the T5 Reflected-Shock Tunnel at Caltech. The KTV scheme utilizes two-photon excitation at 216.67 nm with a pulsed dye laser, followed by re-excitation at 769.45 nm with a continuous laser diode. Results from a nine-shot experimental campaign are presented where N\(_2\) and air gas mixtures are doped with krypton, denoted as 99% N\(_2\)/1% Kr, and 75% N\(_2\)/20% O\(_2\)/5% Kr, respectively. Flow conditions were varied through much of the T5 parameter space (reservoir enthalpy \(h_R\approx 5-16\) MJ/kg). We compare our experimental freestream velocity-profile measurements to reacting, Navier–Stokes nozzle calculations with success, to within the uncertainty of the experiment. Then, we discuss some of the limitations of the present measurement technique, including quenching effects and flow luminosity; and, we present an uncertainty estimate in the freestream velocity computations that arise from the experimentally derived inputs to the code.
Graphic Abstract
中文翻译：
大型高焓反射冲击隧道中的自由流速度剖面测量
摘要
我们应用氪标记测速仪 (KTV) 来测量大型国家级高焓设施——加州理工学院 T5 反射冲击隧道的自由流中的速度剖面。KTV 方案利用脉冲染料激光器在 216.67 nm 处使用双光子激发，然后使用连续激光二极管在 769.45 nm 处再激发。展示了九次实验活动的结果，其中 N \(_2\)和空气气体混合物掺杂有氪，表示为 99% N \(_2\) /1% Kr 和 75% N \(_2\) /20% O \(_2\) /5% Kr，分别。流动条件在 T5 参数空间的大部分（储层焓\(h_R\约 5-16\) 兆焦耳/公斤）。我们将我们的实验自由流速度剖面测量结果与反应的 Navier-Stokes 喷嘴计算成功进行了比较，并在实验的不确定性范围内。然后，我们讨论了当前测量技术的一些局限性，包括淬火效应和流动光度；并且，我们在自由流速度计算中提出了一个不确定性估计，该不确定性估计来自于代码的实验导出输入。
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