scholarly journals Non-Intrusive Measurement of Blade Tip Vibration in Turbomachines

1991 ◽  
Author(s):  
L. Andrenelli ◽  
N. Paone ◽  
G. Rossi ◽  
E. P. Tomasini
Keyword(s):  
Measurement Technique ◽  
Measurement System ◽  
Optical Sensor ◽  
Compressor Blade ◽  
Strain Gages ◽  
Blade Vibration ◽  
Frequency Spectra ◽  
Rotating Blade ◽  
Blade Tip ◽  
Correct Design

It is discussed the need for non-intrusive monitoring of rotating blade vibration. The advantages over conventional techniques are outlined. The vibration of a compressor blade has been investigated by strain gages, with particular attention to time evolution of the frequency spectra, at different operating speeds of the machine. These information are fundamental to the correct design of the non-intrusive measurement system. The non-intrusive measurement technique has been presented, with special attention on uncertainty and resolution. The necessary hardware is discussed and the design of an optical sensor is presented.

scholarly journals An Improved Circumferential Fourier Fit (CFF) Method for Blade Tip Timing Measurements

2020 ◽  
Vol 10 (11) ◽  
pp. 3675
Author(s):  
Zhibo Liu ◽  
Fajie Duan ◽  
Guangyue Niu ◽  
Ling Ma ◽  
Jiajia Jiang ◽  
...  
Keyword(s):  
Development Program ◽  
Time Of Arrival ◽  
Blade Vibration ◽  
Vibration Measurements ◽  
Rotating Speed ◽  
Resonance Analysis ◽  
Rotating Blade ◽  
Negative Effect ◽  
Frequency Identification ◽  
Blade Tip

Rotating blade vibration measurements are very important for any turbomachinery research and development program. The blade tip timing (BTT) technique uses the time of arrival (ToA) of the blade tip passing the casing mounted probes to give the blade vibration. As a non-contact technique, BTT is necessary for rotating blade vibration measurements. The higher accuracy of amplitude and vibration frequency identification has been pursued since the development of BTT. An improved circumferential Fourier fit (ICFF) method is proposed. In this method, the ToA is not only dependent on the rotating speed and monitoring position, but also on blade vibration. Compared with the traditional circumferential Fourier fit (TCFF) method, this improvement is more consistent with reality. A 12-blade assembly simulator and experimental data were used to evaluate the ICFF performance. The simulated results showed that the ICFF performance is comparable to TCFF in terms of EO identification, except the lower PSR or more number probes that have a more negative effect on ICFF. Besides, the accuracy of amplitude identification is higher for ICFF than TCFF on all test conditions. Meanwhile, the higher accuracy of the reconstruction of ICFF was further verified in all measurement resonance analysis.

Design and Experimental Characterization of a Non Intrusive Measurement System of Rotating Blade Vibration

1993 ◽  
Author(s):  
P. Nava ◽  
N. Paone ◽  
G. L. Rossi ◽  
E. P. Tomasini
Keyword(s):  
Measurement System ◽  
Fiber Optic ◽  
Experimental Tests ◽  
Data Acquisition System ◽  
Fiber Optic Sensors ◽  
Experimental Characterization ◽  
Blade Vibration ◽  
Rotating Blade ◽  
Strain Gauge Measurements

A measurement system for non-intrusive monitoring of rotating blade vibration in turbomachines based on fiber optic sensors is presented. The design of the whole system is discussed; the development of special purpose sensors, their interfacing to the data acquisition system and the signal processing are outlined. The processing algorithms are tested by software simulation for several possible blade vibrations. Experimental tests performed on different bladed rotors are presented. Results are compared to simultaneous strain gauge measurements.

Design and Experimental Characterization of a Nonintrusive Measurement System of Rotating Blade Vibration

1994 ◽  
Vol 116 (3) ◽  
pp. 657-662 ◽  
Author(s):  
P. Nava ◽  
N. Paone ◽  
G. L. Rossi ◽  
E. P. Tomasini
Keyword(s):  
Measurement System ◽  
Fiber Optic ◽  
Experimental Tests ◽  
Fiber Optic Sensors ◽  
Experimental Characterization ◽  
Blade Vibration ◽  
Rotating Blade ◽  
Nonintrusive Measurement ◽  
Nonintrusive Monitoring

A measurement system for nonintrusive monitoring of rotating blade vibration in turbomachines based on fiber optic sensors is presented. The design of the whole system is discussed; the development of special purpose sensors, their interfacing to the data acquisition system, and the signal processing are outlined. The processing algorithms are tested by software simulation for several possible blade vibrations. Experimental tests performed on different bladed rotors are presented. Results are compared to simultaneous strain gage measurements.

Compressor Blade Tip Timing Using Capacitance Tip Clearance Probes

2003 ◽  
Author(s):  
Craig Lawson ◽  
Paul Ivey
Keyword(s):  
Compressor Blade ◽  
Tip Clearance ◽  
Test Facility ◽  
Experimental Investigations ◽  
Blade Vibration ◽  
New Instrument ◽  
Timing Measurement ◽  
Measured Strain ◽  
Blade Tip ◽  
Capacitance Probe

Turbomachinery blade vibrations of sufficient amplitude cause High Cycle Fatigue, which reduces blade life. In order to observe this vibration a non-intrusive monitoring system is sought. The vibration can be detected by measuring blade tip timing since in the presence of vibration the blade timing will differ slightly from the passing time calculated from rotor speed. This paper provides new insights into the ability of a commercially available capacitance probe tip clearance measurement system for application as a non-intrusive turbomachinery blade tip timing measurement device. Initial experimental investigations are reported where a compressor blade with mounted strain gauges is used in a low-speed compressor. Capacitance probe results are correlated with simultaneously measured strain gauge results. Finite Element simulations are also used. The performance of the capacitance system in measuring blade vibration is analysed. Measurements were facilitated by the commissioning of a new instrument dedicated compressor test facility and this test facility is described.

Compressor Blade Vibration Measurements Using Blade Image Velocimetry

2015 ◽  
Vol 137 (6) ◽  
Author(s):  
Paul L. Mikrut ◽  
Scott C. Morris ◽  
Joshua D. Cameron
Keyword(s):  
Mass Flow Rate ◽  
Flow Rate ◽  
Measurement Technique ◽  
Vibration Amplitude ◽  
Axial Compressor ◽  
Compressor Blade ◽  
Shaft Speed ◽  
Blade Vibration ◽  
Air Mass ◽  
Image Velocimetry

This paper discusses the application of a novel vibration measurement technique, termed blade image velocimetry (BIV), to a high-speed axial compressor. Measurements of compressor blade vibration can be difficult to obtain and are critical to aeromechanical design validation. The measurement technique discussed in this paper used a commercial particle image velocimetry (PIV) system and was developed as an alternative to conventional measurement techniques such as strain gages and blade tip timing (BTT). The measurement principles and error analysis are reviewed. Methods for estimating the magnitude of random noise corrupting the measurement and validating the vibration amplitude estimates are presented. The technique was validated using a 1.5 stage axial compressor operating at low shaft speed, where it measured the tip velocity to within 0.02% of the true value. The technique was then used to investigate blade vibration at high shaft speed. Low amplitude vibrations in first bending and first torsion were discovered when the compressor was operated at design air-mass flow rate. These vibrations had a maximum tip deflection of 15μm for bending and 7μm for torsion. The vibration amplitude for first bending and first torsion tripled when the compressor was operated at low air mass-flow rate, corresponding to deep stall. Furthermore, excitation of the third eigenmode was also measured. The maximum tip deflections of the first three eigenmodes when the compressor was operated at deep stall were 47μm, 27μm, and 15μm, respectively.

Vibrations of the LH2 Turbine Rotor During the Vinci Engine Test: Tip Timing Measurements and Predictions

2010 ◽  
Author(s):  
Clas Andersson ◽  
Peter Grasbon ◽  
Simon Merchant
Keyword(s):  
Test Data ◽  
Measurement System ◽  
New Technologies ◽  
Turbine Rotor ◽  
Design Tool ◽  
Vibration Measurement ◽  
Successful Implementation ◽  
Blade Vibration ◽  
Blade Tip ◽  
Large Amplitude Vibrations

A test campaign with the purpose of demonstrating new technologies introduced in the Vinci engine was performed in 2008. One of these new technologies is the blisk technology included in the LH2 fuel and LOX oxidizer pump turbines, for which Volvo Aero Corporation has the design responsibility. A challenge with blisks in rotating machinery is the risk of large amplitude vibrations due to low damping. To address the mechanical integrity of the Vinci LH2 turbine rotor blisk with respect to vibrations, an advanced blade vibration measurement system using the blade tip timing method was designed and implemented in close cooperation with the subcontractor AGILIS. The implementation of tip timing for measuring the blade vibrations of the Vinci LH2 blisk was recognized as a challenging application for this kind of measurement system. The conditions in the LH2 turbine are harsh with temperatures down to about 80 K with high pressure and hydrogen environment. Nevertheless, these challenges were systematically investigated rendering a successful implementation. The detailed analysis of the tip timing test data provided unique information for validation. More resonances than expected were confirmed. The responses, however, were modest rendering a low risk for HCF in the test. The most severe resonance in the test with respect to HCF was excited by the second stator harmonics. It was excited several times in the test campaign at about 69200 rpm. This resonance was also pointed out in the design process as being the worst one with respect to HCF. Hence, even though the test data revealed more resonances than expected, the most critical one was identified by the VAC design tool prior to the test. The agreement in predictions and test results for the critical mode was very good with respect to both frequency and response. This statement of very good agreement also applies to the frequencies associated with the other resonances in the test.

Evaluation of an Experimental Testing System for Non-Powered Hand Tools

2000 ◽  
Vol 44 (22) ◽  
pp. 643-646 ◽  
Author(s):  
Tanja Niemelä ◽  
Markku Leppänen ◽  
Minna Päivinen ◽  
Markku Mattila
Keyword(s):  
Measurement System ◽  
Experimental Testing ◽  
Opening Angle ◽  
Emg Activity ◽  
Testing System ◽  
Strain Gages ◽  
Flexor Muscle ◽  
Hand Tools ◽  
Hand Tool ◽  
Forearm Flexor

During the Eurohandtool Project an experimental testing system for non-powered hand tools was developed for laboratory testing. With this system, it is possible to measure simultaneously (1) the EMG activity of two muscles, (2) the opening angle of hand tool blades by means of a potentiometer and, (3) by means of strain gages, the force transmitted to the handle. The first part of evaluation of the system was to determine its time of warming-up, reliability, linearity and repeatability. This paper concentrates on the second part, during which the aim was to test the measurement system by comparing the forces needed to cut wood of a certain diameter, and the actual force required, as measured by a material-testing system. The correlation between forearm flexor muscle activity and the compression force created by the user was investigated. The evaluation of experimental testing system for non-powered hand tools has shown that there are methods to measure force demand, opening angle and EMG-activity simultaneously. However, it is recommended to make some improvements before this measurement system can be taken into widespread use.

An Acoustic System for Pipeline Profile Measurement

1983 ◽  
Vol 105 (4) ◽  
pp. 475-479
Author(s):  
H. Van Calcar
Keyword(s):  
Measurement Technique ◽  
Measurement System ◽  
Performance Enhancement ◽  
Three Dimensional ◽  
Profile Measurement ◽  
Baseline Measurement ◽  
Acoustic System ◽  
Position Measurement ◽  
Long Baseline ◽  
Hardware Configuration

This paper presents an acoustic position measurement system used for precise three-dimensional flowline profile measurement. The system measures several points along the flowline using the long-baseline measurement technique and augments this measurement with depth telemetry repeaters to maintain elevation accuracy throughout the changing installation geometry. The paper discusses both the measurement system and the performance enhancement features. The paper concludes with a discussion of the hardware configuration and the accuracy that can be expected when the technique is extended into deeper operating areas.

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.

Sign in / Sign up

Export Citation Format

Share Document