Temporally and spatially resolved X-ray densitometry in a shock tube
Temporally and spatially resolved X-ray densitometry in a shock tube
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激波管中的时间和空间分辨 X 射线密度测定
DOI：
10.1016/j.combustflame.2020.09.035
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发表时间：
2021
影响因子：
4.4
通讯作者：
Lynch, P.T.
中科院分区：
文献类型：
--
作者：
Shaik, R.A.;Kastengren, A.L.;Tranter, R.S.;Lynch, P.T.
通过X射线吸收光谱法测量气体密度，以检查在微型（12.7 mm口径）高重复率激波管中入射和反射激波后面的密度的空间不均匀性。在氩气中产生冲击波。入射激波后的压力和温度分别为P2 ~ 1.72bar和T2 ~ 800 K，反射激波后的压力和温度分别为P5 ~ 6.5bar和T5 ~ 1480 K。时间分辨线的视线传输测量，使用X射线在9千电子伏光子能量沿着各种轴向和横向位置覆盖整个激波管横截面。将每个位置的X射线透射率转换为路径长度积分密度，在某些条件下，可以进一步转换为路径长度平均密度。测量的气体密度进行了比较，由正常的冲击波关系式计算的，并发现在预冲击和紧后面的入射激波区域的良好协议。对于非常靠近端壁的反射激波条件，也发现了类似的一致性。然而，越来越大的测量和计算的气体密度之间的差异被发现，从端壁的距离增加。重建阿贝尔反演允许的时间和径向分辨密度从横向测量。虽然在这个实验中测得的配置文件是不够的信号噪声水平和分辨率，以明确指定边界层厚度，未来的改进可能能够做到这一点。径向分辨密度揭示了反射激波后气体中不断增长的侧壁热边界层。这些重建进行了比较与模型的热边界层，并与值的热边界层厚度为0.25毫米和1毫米之间，在0.7毫秒后冲击反射。
Gas densities were measured by x-ray absorption spectroscopy to examine spatial inhomogeneity in density behind incident and reflected shock waves in a miniature (12.7 mm bore) high repetition rate shock tube. Shock waves were generated in argon. The pressure and temperature behind the incident shock wereP2~ 1.72 bar andT2~ 800 K, while those behind the reflected shock wereP5~ 6.5 bar andT5~ 1480 K. Time-resolved line-of-sight transmission measurements using x-rays at 9 keV photon energy were made along various axial and transverse locations covering the entire shock tube cross section. The x-ray transmission at each location was converted to pathlength-integrated densities, which in some conditions could be further converted to pathlength-averaged densities. The measured gas densities were compared with those calculated by the normal shock wave relations, and good agreement was found in the pre-shock and immediately behind the incident shock regions. Similar agreement was found for reflected shock conditions very near the endwall. However, increasingly large differences between the measured and calculated gas densities were found as distance from the endwall increased. Reconstruction by Abel inversion allowed time and radially resolved densities to be obtained from the transverse measurements. While the profiles measured in this experiment are of insufficient signal-to noise level and resolution to definitively assign boundary layer thicknesses, future improvements may be able to do this. The radially resolved densities reveal growing sidewall thermal boundary layers in gases behind the reflected shock. These reconstructions were compared with a model of the thermal boundary layer and are consistent with values of the thermal boundary layer thickness being between 0.25 mm and 1 mm at 0.7 ms after shock reflection.
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影响因子：
4.6
作者：
L. Davies;J. Wilson
通讯作者：
L. Davies;J. Wilson
反射激波-边界-层相互作用引起的密度变化
DOI：
--
发表时间：
1966
期刊：
影响因子：
--
作者：
H. B. Dyner
通讯作者：
H. B. Dyner
DOI：
--
发表时间：
1992
期刊：
影响因子：
--
作者：
H. Kleine;V. N. Lyakhov;L. Gvozdeva;H. Grönig
通讯作者：
H. Grönig
影响因子：
3.5
作者：
Qu, Zhechao;Werhahn, Olav;Ebert, Volker
通讯作者：
Ebert, Volker
激波管中入射和反射激波背后的边界层效应
DOI：
--
发表时间：
2012
期刊：
影响因子：
--
作者：
Sijie Li;Wei Ren;D. Davidson;R. Hanson
通讯作者：
R. Hanson