scholarly journals A Non-Uniformly Under-Sampled Blade Tip-Timing Signal Reconstruction Method for Blade Vibration Monitoring

Sensors ◽  
2015 ◽  
Vol 15 (2) ◽  
pp. 2419-2437 ◽  
Author(s):  
Zheng Hu ◽  
Jun Lin ◽  
Zhong-Sheng Chen ◽  
Yong-Min Yang ◽  
Xue-Jun Li
Keyword(s):  
Signal Reconstruction ◽  
Vibration Monitoring ◽  
Reconstruction Method ◽  
Blade Vibration ◽  
Blade Tip

Sparse Reconstruction Method of Non-Uniform Sampling and its Application in Blade Tip Timing System

2020 ◽  
Author(s):  
Jie Tian ◽  
Xiaopu Zhang ◽  
Yong Chen ◽  
Peter Russhard ◽  
Hua Ouyang
Keyword(s):  
Compressive Sensing ◽  
Sparse Reconstruction ◽  
Reconstruction Method ◽  
Blade Vibration ◽  
Uniform Sampling ◽  
Blade Vibrations ◽  
Timing Data ◽  
Blade Tip ◽  
Simultaneous Identification ◽  
Multi Mode

Abstract Based on the blade vibration theory of turbomachinery and the basic principle of blade timing systems, a sparse reconstruction model is derived for the tip timing signal under an arbitrary sensor circumferential placement distribution. The proposed approach uses the sparsity of the tip timing signal in the frequency domain. The application of compressive sensing in reconstructing the blade tip timing signal and monitoring multi-mode blade vibrations is explored. To improve the reconstruction effect, a number of numerical experiments are conducted to examine the effects of various factors on synchronous and non-synchronous signals. This enables the specific steps involved in the compressive sensing reconstruction of tip timing signals to be determined. The proposed method is then applied to the tip timing data of a 27-blade rotor. The results show that the method accurately identifies the multi-mode blade vibrations at different rotation speeds. The proposed method has the advantages of low dependence on prior information, insensitivity to environmental noise, and simultaneous identification of synchronous and non-synchronous signals. The experimental results validate the effectiveness of the proposed approach in engineering applications.

On Possibilities of Using Relative Shaft Vibration Signals for Rotating Blades Monitoring

2018 ◽  
Author(s):  
Jindrich Liska ◽  
Vojtech Vasicek ◽  
Jan Jakl
Keyword(s):  
Steam Turbine ◽  
Operating Conditions ◽  
Vibration Monitoring ◽  
Monitoring Systems ◽  
Blade Vibration ◽  
Vibration Signals ◽  
Rotating Blades ◽  
Timing Measurement ◽  
Blade Tip ◽  
Shaft Vibration

Ensuring the reliability of the steam turbine is the key for its long life. For this purpose monitoring systems are standardly used. Early detection of any failure can avoid possible economical and material losses. A monitoring of rotating blades vibration belongs to the very important tasks of the turbomachinery state assessment. Especially in terms of the last stages of low-pressure part, where the longest blades are vibrating at most. Commonly used methods for blade vibration monitoring are based on contact measurement using strain gauges or non-contact approach based on blade tip timing measurement. Rising demand for low-cost monitoring systems has initiated development of a new approach in blade vibration monitoring task. The presented approach is based on usage of relative rotor vibration signals. Its advantage is in using of standardly installed sensors making this approach economically interesting for the turbine operators compared to the traditionally used methods, mentioned above. This paper summarizes the symptoms of blade vibration phenomenon in relative shaft vibration signals, the impact of operating conditions on the blade vibration amplitude and its comparison to blade tip-timing measurement results. In addition of several examples, the article also describes an evaluation of proposed method in operation of steam turbine with power of 170MW.

scholarly journals Undersampled Blade Tip-Timing Vibration Reconstruction under Rotating Speed Fluctuation: Uniform and Nonuniform Sensor Configurations

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Zhongsheng Chen ◽  
Jing He ◽  
Chi Zhan
Keyword(s):  
Signal Reconstruction ◽  
Reconstruction Error ◽  
Reconstruction Method ◽  
Reconstruction Algorithms ◽  
Rotating Speed ◽  
Rotating Blade ◽  
Reconstruction Methods ◽  
Speed Fluctuation ◽  
Blade Tip ◽  
Sensor Configuration

Blade tip-timing (BTT) is a promising method of online monitoring rotating blade vibrations. Since BTT-based vibration signals are typically undersampled, how to reconstruct characteristic vibrations from BTT signals is a big challenge. Existing reconstruction methods are mainly based on the assumption of constant rotation speeds. However, rotating speed fluctuation is inevitable in many engineering applications. In this case, the BTT sampling process should be nonuniform, which will cause existing reconstruction methods to be unavailable. In order to solve this problem, this paper proposes a new reconstruction method based on nonlinear time transformation (NTT). Firstly, the effects of rotating speed fluctuation on BTT vibration reconstruction are analyzed. Next, the NTT of BTT sampling times under rotating speed fluctuation is presented. Then, two NTT-based reconstruction algorithms are derived for uniform and nonuniform BTT sensor configurations, respectively. Also several evaluation metrics of BTT vibration reconstruction under rotating speed fluctuation are defined. Finally, numerical simulations are done to verify the proposed algorithms. The results testify that the proposed NTT-based reconstruction method can reduce effectively the influence of rotating speed fluctuation and decrease the reconstruction error. In addition, rotating speed fluctuation has more bad effects on the reconstruction method under nonuniform sensor configuration than under uniform sensor configuration. For nonuniform BTT signal reconstruction under rotating speed fluctuation, more attentions should be paid on selecting proper angles between BTT sensors. In summary, the proposed method will benefit for detecting early blade damages by reducing frequency aliasing.

Sparse reconstruction of blade tip-timing signals for multi-mode blade vibration monitoring

2016 ◽  
Vol 81 ◽  
pp. 250-258 ◽  
Author(s):  
Jun Lin ◽  
Zheng Hu ◽  
Zhong-Sheng Chen ◽  
Yong-Min Yang ◽  
Hai-Long Xu
Keyword(s):  
Vibration Monitoring ◽  
Sparse Reconstruction ◽  
Blade Vibration ◽  
Blade Tip ◽  
Multi Mode

scholarly journals A Torsional Vibration Measurement Method for Rotating Blades Based on Blade Tip Timing

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Haonan Guo ◽  
Yongmin Yang ◽  
Fengjiao Guan ◽  
Haifeng Hu ◽  
Guoji Shen ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Torsional Vibration ◽  
Measurement Method ◽  
Optimization Method ◽  
Vibration Monitoring ◽  
Vibration Measurement ◽  
Stable Operation ◽  
Blade Vibration ◽  
Blade Tip ◽  
Types Of Faults

During the working process of the turbine, some types of faults can cause changes in the vibration characteristics of the blades. The real-time vibration monitoring of the blades is of great significance to the stable operation and state-based maintenance. Torsional vibration is a kind of blade vibration modes and results in failures such as cracks easily. Thus, it is important to measure it due to the harmfulness of torsional vibration. Firstly, the principle of blade tip timing (BTT) is introduced, and the models of the blade are built to analyze the characteristics of torsional vibration. Then, the compressed sensing theory is introduced, and its related parameters are determined according to the measurement requirements. Next, based on the condition that the blade rigidity axis is not bent and bent, respectively, the layout method of sensors is proposed and the numerical simulation of the measurement process is performed. The results of the above two types of numerical simulation verify the proposed measurement method. Finally, by analyzing the influencing factors of measurement uncertainty, the optimization method of sensors’ layout is further proposed. This study can provide important theoretical guidance for the measurement of blade torsional vibration.

scholarly journals Application of Blade-Tip Sensors to Blade-Vibration Monitoring in Gas Turbines

10.5772/29550 ◽  
2012 ◽  
Author(s):  
Ryszard Szczepanik ◽  
Radosaw Przysowa ◽  
Jarosaw Spychaa ◽  
Edward Rokicki ◽  
Krzysztof Kazmierczak ◽  
...  
Keyword(s):  
Gas Turbines ◽  
Vibration Monitoring ◽  
Blade Vibration ◽  
Blade Tip

Image Reconstruction with the Fourier Coefficients for Magnetic Induction Tomography

2020 ◽  
Vol 16 (2) ◽  
pp. 156-163
Author(s):  
Jingwen Wang ◽  
Xu Wang ◽  
Dan Yang ◽  
Kaiyang Wang
Keyword(s):  
Inverse Problem ◽  
Image Reconstruction ◽  
Magnetic Induction ◽  
Fourier Coefficients ◽  
Signal Reconstruction ◽  
Reconstruction Algorithm ◽  
Reconstruction Method ◽  
Measurement Equation ◽  
Image Reconstruction Method ◽  
Magnetic Induction Tomography

Background: Image reconstruction of magnetic induction tomography (MIT) is a typical ill-posed inverse problem, which means that the measurements are always far from enough. Thus, MIT image reconstruction results using conventional algorithms such as linear back projection and Landweber often suffer from limitations such as low resolution and blurred edges. Methods: In this paper, based on the recent finite rate of innovation (FRI) framework, a novel image reconstruction method with MIT system is presented. Results: This is achieved through modeling and sampling the MIT signals in FRI framework, resulting in a few new measurements, namely, fourier coefficients. Because each new measurement contains all the pixel position and conductivity information of the dense phase medium, the illposed inverse problem can be improved, by rebuilding the MIT measurement equation with the measurement voltage and the new measurements. Finally, a sparsity-based signal reconstruction algorithm is presented to reconstruct the original MIT image signal, by solving this new measurement equation. Conclusion: Experiments show that the proposed method has better indicators such as image error and correlation coefficient. Therefore, it is a kind of MIT image reconstruction method with high accuracy.

Interpolation method for wideband signal reconstruction based on blade tip timing measurement

Measurement ◽  
2021 ◽  
Vol 176 ◽  
pp. 109168
Author(s):  
Suiyu Chen ◽  
Yongmin Yang ◽  
Haifeng Hu ◽  
Fengjiao Guan ◽  
Guoji Shen ◽  
...  
Keyword(s):  
Interpolation Method ◽  
Signal Reconstruction ◽  
Wideband Signal ◽  
Timing Measurement ◽  
Blade Tip
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