Numerical processing of thin-film thermometer data for determining transient heat fluxes

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• 作者：E. Bertolazzi^a ; L. Battisti^a ; F. Trivellato^b ; ^{trivella@ing.unitn.it}
• 关键词：Thin-film ; Heat transfer ; Data reduction ; Finite element
• 刊名：Applied Mathematical Modelling
• 出版年：2012
• 期刊代码：6_0307904x
• 类别：cp
• 出版时间：August, 2012
• 卷：36
• 期：8
• 页码：3645-3662
• 文件大小：964 K

摘要

The purpose of this study is the evaluation of transient heat fluxes using thin-film thermometer data. A thin-film temperature sensor operated in transient mode enables very accurate surface temperature measurements (e.g., in turbine blades or in hypersonic wind tunnels), which are obtained because the gauge is non-intrusive and has a high frequency response; however, the complexity of data processing is the major drawback for the popular use of the thin-film sensor.

The performances of present methodologies for data reduction are here improved, leading to a new implicit method; in addition, a new numerical concept of data reduction is presented: it includes a comprehensive 1-D finite element model which is convenient both for its capability of dealing with the most general boundary conditions and for the low computational cost as compared to the present transform-based methods.

The proposed finite element method can tackle the single- and the double-layer sensor, temperature dependent properties of the sensor and, more importantly, it can be applied when the semi-infinite assumption is no longer feasible; it proved successful in processing prototype signals for Mach numbers in the range 0.02-6. The analytical calculation of the accuracy of all the methods is also new and it prompts a guideline that is useful to design a priori an experiment on rational basis.