Toluene-based planar laser-induced fluorescence imaging of temperature in hypersonic flows
Toluene-based planar laser-induced fluorescence imaging of temperature in hypersonic flows
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DOI：
10.1007/s00348-015-1987-6
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发表时间：
2015-05
影响因子：
2.4
通讯作者：
D. Estruch-Samper;L. Vanstone;R. Hillier;B. Ganapathisubramani
中科院分区：
文献类型：
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作者：
D. Estruch-Samper;L. Vanstone;R. Hillier;B. Ganapathisubramani
平面激光诱导荧光成像在高超声速枪道中进行，自由流马赫数为8.9，雷诺数为（测试气体）。随着温度的升高，甲苯的荧光与发射光谱的红移相关。使用双色方法，在 266 nm 处激发后，使用两个不同的滤光片在单独的运行中捕获两个不同波段的发射光谱。使用这种方法研究了两种不同的流场：（i）经过钝头的高超音速流，其特征是具有强熵效应的弓激波，以及（ii）由位于同一钝圆柱体下游的耀斑引起的附加冲击波/边界层相互作用。从低至 K 的自由流温度一直到 Kare 的测量值均已获得。较高温度水平的不确定性约为 %，而在温度低端，预计会有额外的 % 不确定性。由于荧光量子产率呈指数降低以及停滞区 (K) 附近发生甲苯热解，该技术的应用在高温下受到进一步挑战。总体而言，结果与预期分布一致，从而证明了该技术适用于低焓设施中的高超音速流动测温应用。
Planar laser-induced fluorescence imaging is carried out in a hypersonic gun tunnel at a freestream Mach number of 8.9 and Reynolds number of(is the test gas). The fluorescence of tolueneis correlated with the red shift of the emission spectra with increasing temperature. A two-colour approach is used where, following an excitation at 266 nm, emission spectra at two different bands are captured in separate runs using two different filters. Two different flow fields are investigated using this method: (i) hypersonic flow past a blunt nose, which is characterised by a bow shock with strong entropy effects, and (ii) an attached shock-wave/boundary-layer interaction induced by a flare located further downstream on the same blunt cylinder body. Measurements from as low as the freestream temperature ofK all the way up toKare obtained. The uncertainty at the higher temperature level is approximately%, while at the low end of the temperature, an additional% uncertainty is expected. Application of the technique is further challenged at high temperatures due to the exponentially reduced fluorescence quantum yields and the occurrence of toluene pyrolysis near the stagnation region (K). Overall, results are found to be within% agreement with the expected distributions, thus demonstrating suitability of the technique for hypersonic flow thermometry applications in low-enthalpy facilities.