Implementation of an In-Situ Infrared Calibration Method for Precise Heat Transfer Measurements on a Linear Cascade
Implementation of an In-Situ Infrared Calibration Method for Precise Heat Transfer Measurements on a Linear Cascade
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DOI：
10.1115/1.4041132
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发表时间：
2019-02-01
影响因子：
1.7
通讯作者：
Niehuis, Reinhard
中科院分区：
文献类型：
--
作者：
Aberle, Svenja;Bitter, Martin;Niehuis, Reinhard
针对线性叶栅中心叶片的传热测量，建立了红外测量技术。作为一个极具挑战性的条件，红外信号的角依赖性被识别出来。除了受几何条件限制的浅视角外，弯曲的叶片表面也需要考虑这种依赖性。因此，建立了一种强大的原位标定方法，该方法隐式地考虑了角度依赖性。与通常的程序不同，测量的红外强度和温度的相关性通过叶片上每个位置的单独校准函数进行校准。总共进行了三种不同的校准方法并进行了评估。与通常的全局校准相比，低速测试条件下的初始测量使用本地校准提供了物理上更合理的结果。通过这些数据，可以对叶栅的气动特性进行评估。经过少量修改，该程序能够在喷气推进研究所的高速叶栅风洞中提供高精度的传热测量。
For heat transfer measurements on the center blade of a linear cascade, the infrared measurement technique was set up. As a highly challenging condition, the angular dependency of the infrared signal was identified. Beside a shallow angle of view, limited by geometric conditions, the curved blade surface necessitated the consideration of this dependency. Therefore, a powerful in-situ calibration method was set up, which accounts for the angular dependency implicitly. In contrast to usual procedures, the correlation of the measured infrared intensity and the temperature was calibrated by a separate calibration function for each position on the blade. In all, three different calibration approaches were proceeded and assessed. Initial measurements in low-speed test conditions delivered physically more reasonable results, using a local calibration compared to a usual global calibration. By means of these data, an evaluation of the aerodynamic characteristic of the cascade was enabled. With few modifications, the procedure is capable to deliver high-precision heat transfer measurements in the high-speed cascade wind-tunnel at the Institute of Jet Propulsion.