scholarly journals Improved Blade Tip Timing in Blade Vibration Monitoring with Torsional Vibration of the Rotor

2012 ◽  
Vol 364 ◽  
pp. 012136 ◽  
Author(s):  
Chao Liu ◽  
Dongxiang Jiang
Keyword(s):  
Torsional Vibration ◽  
Vibration Monitoring ◽  
Blade Vibration ◽  
Blade Tip

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.

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 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 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 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

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.

New Step to Improve the Accuracy of Blade Synchronous Vibration Parameters Identification Based on Combination of GARIV and LM Algorithm

2017 ◽  
Author(s):  
Weimin Wang ◽  
Sanqun Ren ◽  
Shan Huang ◽  
Qihang Li ◽  
Kang Chen
Keyword(s):  
Experimental Study ◽  
Parameters Identification ◽  
Least Square ◽  
Experimental Result ◽  
Blade Vibration ◽  
Vibration Displacement ◽  
Campbell Diagram ◽  
Identification Method ◽  
Blade Tip ◽  
Vibration Parameters

Generally, turbine blade vibration can be divided into asynchronous vibration and synchronous vibration. Comparing to parameters identification of asynchronous vibration, that of the synchronous vibration is more difficult and needs more sensors. The applicability of the synchronous identification method is more stringent than that of asynchronous identification method. A new method is presented to identify the blade synchronous vibration parameters based on the blade tip-timing (BTT) method and previous achievements in this region. Here, the parameters, such as the frequency of harmonic resonance center, blade vibration amplitude and the initial phase, are obtained by the nonlinear least square fitting algorithm based on relationships between the rotation speed and the blade tip displacement. We call this way as sweep frequency fitting (SFF) method. As the blade is operated at a constant speed that is near the frequency of resonance center, the blade vibration displacement can be obtained by the sensors at different positions, so the blade synchronous vibration Engine Order (EO) can be obtained by the global autoregressive with instrumental variables (GARIV) method. Furthermore the Campbell diagram of blade synchronous vibration can be plotted by the parameters obtained by GARIV method and SFF method. In the experimental study, the parameter identification of blade synchronous vibration is completed and the Campbell diagram of blade vibration is accurately plotted under the excitation of six magnets. Meanwhile, the experimental study and analysis on the harmonic vibration of blade with different numbers of excitation are carried out. The relative deviation of the dynamic frequency of blade between the experimental result and simulation result is less than 1%.

scholarly journals A Nonintrusive Rotor Blade Vibration Monitoring System

1996 ◽  
Author(s):  
Henry Jones
Keyword(s):  
Rotor Blade ◽  
Rotating Machinery ◽  
Vibration Monitoring ◽  
Static Deflection ◽  
Blade Vibration ◽  
Turbine Engine ◽  
Measurement Systems ◽  
Timing Data ◽  
On Line ◽  
Engine Rotor

A technique for measuring turbine engine rotor blade vibrations has been developed as an alternative to conventional strain-gage measurement systems. Light probes are mounted on the periphery of the engine rotor casing to sense the precise blade passing times of each blade in the row. The timing data are processed on-line to identify (1) individual blade vibration amplitudes and frequencies, (2) interblade phases, (3) system modal definitions, and (4) blade static deflection. This technique has been effectively applied to both turbine engine rotors and plant rotating machinery.

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