Development of On-Line Monitoring Systems for High Temperature Components in Power Plants

Zhang, Hongcai; Jia, Jiuhong; Wang, Ning; Hu, Xiaoyin; Tu, Shan‐Tung; Zhou, Shaoping; Wang, Zhengdong

doi:10.3390/s131115504

Cited by 12 publications

(6 citation statements)

References 11 publications

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“…However, traditional strain gauges are not reliable for prolonged measurements at high temperatures [2], in addition to nonlinearity of thermal-induced apparent strains and susceptibility to electromagnetic interference (EMI). Measurement accuracy with optical strain gauges and digital image correlation (DIC) is also adversely affected by insufficient image quality due to the inevitable degradation of markers exposed to high temperatures with time [3].…”

Section: Introductionmentioning

confidence: 99%

An Improved Metal-Packaged Strain Sensor Based on A Regenerated Fiber Bragg Grating in Hydrogen-Loaded Boron–Germanium Co-Doped Photosensitive Fiber for High-Temperature Applications

Zhou

et al. 2017

Sensors

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Local strain measurements are considered as an effective method for structural health monitoring of high-temperature components, which require accurate, reliable and durable sensors. To develop strain sensors that can be used in higher temperature environments, an improved metal-packaged strain sensor based on a regenerated fiber Bragg grating (RFBG) fabricated in hydrogen (H2)-loaded boron–germanium (B–Ge) co-doped photosensitive fiber is developed using the process of combining magnetron sputtering and electroplating, addressing the limitation of mechanical strength degradation of silica optical fibers after annealing at a high temperature for regeneration. The regeneration characteristics of the RFBGs and the strain characteristics of the sensor are evaluated. Numerical simulation of the sensor is conducted using a three-dimensional finite element model. Anomalous decay behavior of two regeneration regimes is observed for the FBGs written in H2-loaded B–Ge co-doped fiber. The strain sensor exhibits good linearity, stability and repeatability when exposed to constant high temperatures of up to 540 °C. A satisfactory agreement is obtained between the experimental and numerical results in strain sensitivity. The results demonstrate that the improved metal-packaged strain sensors based on RFBGs in H2-loaded B–Ge co-doped fiber provide great potential for high-temperature applications by addressing the issues of mechanical integrity and packaging.

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Section: Introductionmentioning

confidence: 99%

An Improved Metal-Packaged Strain Sensor Based on A Regenerated Fiber Bragg Grating in Hydrogen-Loaded Boron–Germanium Co-Doped Photosensitive Fiber for High-Temperature Applications

Zhou

et al. 2017

Sensors

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“…However, the leakage behavior is easy to occur near the minimum rotation angle region owing to the significant decrease of gasket stress. Therefore, the minimum and the maximum rotation angles and their locations of flange The included angle β can be expressed as (22) The rotation angle under external bending moment can be expressed as: (23) It should be noted that α1=α4, and α2=α3=0 under the pretightening and internal pressure condition.…”

Section: Calculation Of the Rotation Angle Of Flange Jointsmentioning

confidence: 99%

“…Therefore, the rigidity and amplification, which are regarded as the key parameters of flexure-hinge mechanisms, are widely investigated by many researchers in recent years [19,20,21,22] . Recently, Tu and Xuan et al [23,24,25,26] developed various extensometers to monitor the creep strain of pipeline at elevated temperature, especially by magnifying mechanisms. However, according to the best knowledge of authors, very few references introduced the deformation monitoring of bolted flange joints during the assemble or operation process, especially the rotation angle of flange.…”

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confidence: 99%

Measurement of small rotation angle of flange joints by a novel flexure magnifying mechanism

et al. 2019

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Bolted flange joints are indispensable components in process industries due to the good sealing, assemble and disassemble capacities. Generally, the flange rigidity characterized by the rotation angle is a key index to evaluate the sealing tightness of flange joints. However, the rotation angle of flange is usually too small (less than 1º) to monitor during the assemble and operation stages. Accordingly, a novel flexure magnifying mechanism is designed to measure the small rotation angle of flange joints under internal pressure and external bending moment. The magnification factor and calculation approach of the flexure amplification mechanism are deduced and verified by experimental data and finite element simulation. Results indicate that the proposed measuring apparatus has good performance to monitor the maximum rotation angle. It is of great interest that the measured location of the maximum rotation angle is in good agreement with that in the experiment, and the average error is 7.3%, which is acceptable for practical application. Additionally, the leakage rate at the top of flange joints slowly and almost linearly increases with the increment of external bending moment ascribing to the decrease the gasket stress near the top of flange joints.

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“…There are many pressure vessels and pipes working in harsh environments, e.g., high temperature or corrosive. Online monitoring of the wall thinning caused by erosion or corrosion is very important for the safe operation of such equipment utilizing permanently installed transducers [1][2][3]. However, transducers will suffer from depolarization when they are exposed to high temperature or corrosion for a long time which considerably limits the application for conventional sensory devices in structural health monitoring (SHM) and non-destructive evaluation [4,5].…”

Section: Introductionmentioning

confidence: 99%

Optimal Design Methodology of Tapered Waveguide Transducers for Thickness Monitoring

Jia

Ren

Wang

et al. 2020

Sensors

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For the purpose of providing transducers for long-term monitoring of wall thinning of critical pressure equipment in corrosion or high temperature environments, the optimal design methodology for tapered waveguide units was proposed in the present study. Firstly, the feasibility of the quasi-fundamental shear horizontal (SH0*) wave propagating in the tapered waveguide units was analyzed via numerical simulations, and the transmitting limitations of the non-dispersive SH0* wave were researched. Secondly, several tapered waveguide transducers with varying cross-sections to transmit pure SH0* wave were designed according to the numerical results. Experimental investigations were carried out, and the results were compared with waveguide transducers with a prismatic cross-section. It was found that the tapered waveguide units can transmit non-dispersive shear horizontal waves and suppress the wave attenuation at the same time. The experimental results agreed very well with the numerical simulations. Finally, high-temperature experiments were carried out, and the reliability of thickness measuring by the tapered waveguide transducers was validated. The errors between the measured and the true thicknesses were small. This work paves a solid foundation for the optimal design of tapered waveguide transducers for thickness monitoring of equipment in harsh environments.

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Development of On-Line Monitoring Systems for High Temperature Components in Power Plants

Cited by 12 publications

References 11 publications

An Improved Metal-Packaged Strain Sensor Based on A Regenerated Fiber Bragg Grating in Hydrogen-Loaded Boron–Germanium Co-Doped Photosensitive Fiber for High-Temperature Applications

An Improved Metal-Packaged Strain Sensor Based on A Regenerated Fiber Bragg Grating in Hydrogen-Loaded Boron–Germanium Co-Doped Photosensitive Fiber for High-Temperature Applications

Measurement of small rotation angle of flange joints by a novel flexure magnifying mechanism

Optimal Design Methodology of Tapered Waveguide Transducers for Thickness Monitoring

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