Abstract Fast-response coaxial surface junction thermocouples have been used to measure time-resolved stagnation temperature of the Mach 6 flow produced by the University of Southern Queensland’s hypersonic wind tunnel, TUSQ. The piston compression and the nozzle expansion of the test gas were found to be approximately isentropic for the first 65 ms of flow. Thereafter, the stagnation temperature reduces from T 0 ≈ 560 K due to the heat lost to the cold barrel, and this process can be modelled based on the measured barrel pressure history to simulate the stagnation temperature in TUSQ to within 2% of the actual value for the first 150 ms of flow. By operating the thermocouples at the flow stagnation temperature, the fluctuations of the flow stagnation temperature were investigated. A 3–4 kHz narrowband stagnation temperature fluctuation appearing after t ≈ 65 ms was measured, and found to be correlated with the transition to turbulence of the flow in the barrel.

中文翻译：

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使用表面结热电偶测量高超声速流动中的时间分辨停滞温度

摘要 快速响应同轴表面结热电偶已被用于测量由南昆士兰大学高超声速风洞 TUSQ 产生的 6 马赫气流的时间分辨停滞温度。发现测试气体的活塞压缩和喷嘴膨胀在前 65 毫秒的流动中近似等熵。此后，由于冷却机筒的热量损失，停滞温度从 T 0 ≈ 560 K 降低，并且可以根据测量的机筒压力历史对该过程进行建模，以模拟 TUSQ 中的停滞温度到实际值的 2% 以内对于前 150 毫秒的流量。通过在滞流温度下操作热电偶，研究了滞流温度的波动。