High-Temperature Profile Monitoring in Gas Turbine Exhaust-Gas Diffusors with Six-Point Fiber-Optic Sensor Array

Dutz, Franz J.; Boje, Sven; Orth, Ulrich R.; Koch, Alexander W.; Roths, Johannes

doi:10.3390/ijtpp5040025

Cited by 18 publications

(6 citation statements)

References 14 publications

(14 reference statements)

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“…RFBGs were used to monitor the temperature of a melt during metal processing [ 19 ], the temperature of a turbo engine exhaust [ 20 ], during structural fire testing [ 21 ] and for measurement of the temperature distribution inside the substrate during a MCVD process [ 22 ]. An array of six RBFGs was used to thermally map the exhaust of a gas turbine [ 23 ] and 24 RFBGs incorporated into six fibers were used to monitor the temperature profile of a catalytic fixed-bed tubular reactor for more than two years [ 24 ].…”

Section: Introductionmentioning

confidence: 99%

Fiber Bragg Grating Wavelength Drift in Long-Term High Temperature Annealing

Grobnic

Hnatovsky

Dedyulin

et al. 2021

Sensors

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High-temperature-resistant fiber Bragg gratings (FBGs) are the main competitors to thermocouples as sensors in applications for high temperature environments defined as being in the 600–1200°C temperature range. Due to their small size, capacity to be multiplexed into high density distributed sensor arrays and survivability in extreme ambient temperatures, they could provide the essential sensing support that is needed in high temperature processes. While capable of providing reliable sensing information in the short term, their long-term functionality is affected by the drift of the characteristic Bragg wavelength or resonance that is used to derive the temperature. A number of physical processes have been proposed as the cause of the high temperature wavelength drift but there is yet no credible description of this process. In this paper we review the literature related to the long-term wavelength drift of FBGs at high temperature and provide our recent results of more than 4000 h of high temperature testing in the 900 –1000°C range. We identify the major components of the high temperature wavelength drift and we propose mechanisms that could be causing them.

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Section: Introductionmentioning

confidence: 99%

Fiber Bragg Grating Wavelength Drift in Long-Term High Temperature Annealing

Grobnic

Hnatovsky

Dedyulin

et al. 2021

Sensors

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“…Fiber Bragg Gratings (FBGs) are key components for sensing (e.g., temperature or strain) because of their small size, their immunity to electromagnetic interferences and their ability to withstand high pressures and temperatures [1]. Over the last few decades, FBGs inscribed with femtosecond (fs) lasers stood out due to their exceptional thermal stability [2,3], making them suitable for various applications in harsh environments such as in the oil and gas industries [4,5], noble metals recycling, nuclear power plants [6], aerospace turbines [7], or laser additive manufacturing [8]. Different fs-types of FBGs exist, depending on the nature of refractive index modifications and underlying nano-structural changes that are induced by the fs-laser pulses, such as Type I, II or III [9,10,11].…”

Section: Introductionmentioning

confidence: 99%

High temperature behavior of femtosecond laser photo-inscribed micro-voids

Sosa,

Cavillon,

Blanchet

et al. 2024

Laser + Photonics for Advanced Manufacturing

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Fiber Bragg gratings are widely used for optical sensing applications, including their deployment in harsh environments. The use of Type III femtosecond gratings shows a prominent interest due to their ability to withstand very high temperatures (over 1000°C for 100's of hours). These Type III fiber Bragg gratings correspond to a periodic structure of micro-voids generated by femtosecond-laser in silica-based optical fibers, fabricated by the point-by-point technique. The physicochemical characteristics of the micro-voids were investigated by quantitative phase microscopy technique and their thermal stability monitored through isochronal annealing experiments up to 1250°C.

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“…Another way is the method of indirect parametric diagnostics, which can be characterized as object monitoring by evaluating a selected parameter, which is directly related to the functional purpose of the object and directly characterizes its technical condition. This method can be applied to those not equipped with standard diagnostic systems GTUs or to improve the accuracy of staff systems, for example, for diagnosing overpressure, pressure drop, temperature, rotor speed, thrust, and others [3][4][5]. In article [6], the authors describe the use of a diagnostic model for the state of the combustion chamber, turbine, and centrifugal compressor.…”

Section: Introductionmentioning

confidence: 99%

Non-Invasive Acoustic Monitoring of Gas Turbine Units by Fiber Optic Sensors

Stepanov

Zhirnov

Sazonkin

et al. 2022

Sensors

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In this article, we study the possibility of gas turbine unit (GTU) monitoring using interferometric fiber optic sensors. We used the Mach–Zehnder interferometer (MZI) scheme, which can be easily implemented and simply installed on the turbine, and also allows us to solve the problem of phase unwrapping conveniently. In this research, the following main steps were carried out: an experimental scheme based on the MZI was assembled, and its sensitive arm was fixed on the GTU under study; data on various operation modes of the GTU was collected; the data were subjected to frequency FFT analysis, based on which the main rotational speeds of the turbine were identified. With FFT analysis, we also demonstrated multiples harmonics, which appear in the case of GTU after operating time, caused by the number of blades. The possibility of GTU monitoring and analysis using a non-invasive compact fiber-optic sensor is demonstrated: spectral analysis is used to detect the rotor speed, as well as the presence or absence of high-order multiple frequencies indicating blade and bearing defects, which are determined by the number of GTU’s blades and rolling bearing used as turbines rotor supports.

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High-Temperature Profile Monitoring in Gas Turbine Exhaust-Gas Diffusors with Six-Point Fiber-Optic Sensor Array

Cited by 18 publications

References 14 publications

Fiber Bragg Grating Wavelength Drift in Long-Term High Temperature Annealing

Fiber Bragg Grating Wavelength Drift in Long-Term High Temperature Annealing

High temperature behavior of femtosecond laser photo-inscribed micro-voids

Non-Invasive Acoustic Monitoring of Gas Turbine Units by Fiber Optic Sensors

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