Effect of pyrometer type and wavelength selection on temperature measurement errors for turbine blades

Liu, Dong; Feng, Chi; Gao, Shan; Daniel, Ketui; Chen, Liwei

doi:10.1016/j.infrared.2018.09.004

Cited by 19 publications

(6 citation statements)

References 24 publications

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“…By using the suggested approach, the impact of the environment on radiance is evaluated, and it can be considered to have no further influence on the calculated absolute temperature and emissivity of the samples. Taking into account all the aforementioned assumptions and referring to the findings of Li et al [28], the expression for the observed radiance can be defined as the Equation (3):…”

Section: Influence Of the Environment On The Measurementmentioning

confidence: 99%

In-Situ Pixel-wise Emissivity Measurement Using a Multispectral Infrared Camera

Poissenot-Arrigoni,

Marcon,

Rossi

et al. 2023

J. Imaging

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In the thermography process, accurately determining emissivity is crucial to obtain precise temperature measurements as it enables the conversion of radiometric values to absolute temperatures. However, assessing emissivity is not a straightforward task as it depends on various other parameters. Traditional methods for measuring emissivity often involve costly materials and cannot be carried out simultaneously with infrared image acquisition. This article presents a method for obtaining pixel-wise emissivity using data from a multispectral infrared camera. Consequently, this method allows for direct emissivity measurement during infrared camera acquisition without the need for additional materials or experiments.

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Section: Influence Of the Environment On The Measurementmentioning

confidence: 99%

In-Situ Pixel-wise Emissivity Measurement Using a Multispectral Infrared Camera

Poissenot-Arrigoni,

Marcon,

Rossi

et al. 2023

J. Imaging

View full text Add to dashboard Cite

show abstract

“…By using the suggested approach, the impact of the environment on radiance will be evaluated, and it can be considered to have no further in uence on the calculated absolute temperature and emissivity of the samples. Taking into account all the aforementioned assumptions and referring to the ndings of Li et al [24], the expression for the observed radiance can be de ned as the Eq. 3:…”

Section: Hypothesismentioning

confidence: 99%

In-situ pixel wise emissivity measurement using a multispectral infrared camera

Poissenot-Arrigoni

Marcon

Rossi

et al. 2023

Preprint

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In the thermography process, accurately determining emissivity is crucial for obtaining precise temperature measurements as it enables the conversion of radiometric values to absolute temperatures. However, assessing emissivity is not a straightforward task as it depends on various other parameters. Traditional methods for measuring emissivity often involve costly materials and cannot be carried out simultaneously with infrared image acquisition. This article presents a method for obtaining pixel-wise emissivity using data from a multispectral infrared camera. Consequently, this method allows for direct emissivity measurement during infrared camera acquisition without the need for additional materials or experiments.

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“…For accurate results the emittance of the blades must be measured prior to installation to later be used in correcting the output of the pyrometer, however the emittance is also affected by factors such as surface roughness, oxidation state, and chemical composition, which will affect the overall accuracy of the system. A number of solutions have been proposed to improve the accuracy of emittence measurement, namely dual and triple wavelength pyrometry [5,51]. A review of multi-spectral pyrometry systems is given by Araújo et al [52].…”

Section: Pyrometrymentioning

confidence: 99%

Surface temperature condition monitoring methods for aerospace turbomachinery: exploring the use of ultrasonic guided waves

Yule

Zaghari

Harris

et al. 2021

Meas. Sci. Technol.

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Turbine blades and nozzle guide vanes (NGVs) are operated at extreme temperatures in order to maximise thermal efficiency and power output of an engine. In this paper the suitability of existing temperature monitoring systems for turbine blades and nozzle guide vanes are reviewed. Both offline and online methods are presented and their advantages and disadvantages are examined. The use of offline systems is well established but their online equivalents are difficult to implement because of the limited access to components. There is the need for an improved sensor that is capable of measuring temperature in real time with minimum interference to the operating conditions of the engine, allowing operating temperatures to be increased to the limits of the components and maximising efficiency. Acoustic monitoring techniques are already used for a large number of structural health monitoring applications and have the potential to be adapted for use in temperature monitoring for turbine blades and NGVs. High temperatures severely affect the response of ultrasonic transducers. However, waveguides and buffer rods can be used to distance transducers from extreme conditions, while piezoelectric materials such as Yttrium Calcium Oxyborate single crystals and Aluminum Nitride have been developed for use at high temperatures. A new monitoring approach based on ultrasonic guided waves is introduced in this paper. The geometry of turbine blades and NGVs allows Lamb waves to propagate through their structure, and the presence of numerous cooling holes will produce acoustic reflections that can be utilised for monitoring temperature at a number of locations. The dispersive nature of Lamb waves makes their analysis difficult; however, wave velocity in dispersive regions is particularly sensitive to changes in temperature and could be utilised for monitoring purposes. The proposed method has the potential to provide high resolution and accuracy, fast response times, and the ability to place sensors outside of the gas path. Further research is required to develop a monitoring system based on the use of guided waves in extreme environments.

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Effect of pyrometer type and wavelength selection on temperature measurement errors for turbine blades

Cited by 19 publications

References 24 publications

In-Situ Pixel-wise Emissivity Measurement Using a Multispectral Infrared Camera

In-Situ Pixel-wise Emissivity Measurement Using a Multispectral Infrared Camera

In-situ pixel wise emissivity measurement using a multispectral infrared camera

Surface temperature condition monitoring methods for aerospace turbomachinery: exploring the use of ultrasonic guided waves

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