The Use of Eddy Current Sensor Based Blade Tip Timing for FOD Detection

2008 ◽  
Author(s):  
K. S. Chana ◽  
D. N. Cardwell
Keyword(s):  
Eddy Current ◽  
Low Cycle Fatigue ◽  
Rotor Blades ◽  
Current Sensor ◽  
Foreign Object ◽  
Cycle Fatigue ◽  
Blade Vibration ◽  
Arrival Times ◽  
Foreign Object Damage ◽  
Eddy Current Sensor

Deterioration of rotor blades due to foreign object damage (FOD), erosion by sand/water, low cycle fatigue (LCF) and high cycle fatigue (HCF) all limit blade life, but cannot always be detected before a failure. The advent of tip-timing systems makes it possible to assess turbomachinery blade vibration using non-contact systems. However, these systems are still largely optical based and therefore suffer from contamination problems, further development of these systems is difficult due to problems associated with keeping the sensors clean. Experimental measurements have been carried out using an alternative eddy current sensor that has been validated in a series of laboratory and engine tests to measure rotor blade arrival times. A series of engine trials have been conducted to assess their capability for detection of pre-existing damage and the capture of dynamic foreign object damage (FOD) events. The results show that it is possible to acquire high quality blade timing data for use in engine condition monitoring. In addition for the detection of FOD created damage and FOD damage as it occurs.

The Use of Eddy Current Sensors for the Measurement of Rotor Blade Tip Timing: Sensor Development and Engine Testing

2008 ◽  
Author(s):  
D. N. Cardwell ◽  
K. S. Chana ◽  
P. Russhard
Keyword(s):  
Eddy Current ◽  
Rotor Blade ◽  
Service Use ◽  
Optical Systems ◽  
Current Sensor ◽  
Blade Vibration ◽  
Arrival Times ◽  
Eddy Current Sensor ◽  
Blade Tip ◽  
Engine Testing

The advent of tip-timing systems makes it possible to assess turbomachinery blade vibration using non-contact systems. Currently, the most widely used systems in industry are optical systems. However, these systems are still only used on development engines, largely because of contamination problems from dust, dirt, oil, water etc. Further development of these systems for in-service use is problematic because of the difficulty of eliminating contamination of the optics. Hence, alternatives need to be developed that are immune to contamination but have equivalent resolution and bandwidth as the optical system. Experimental measurements have been carried out using alternative sensors. An eddy current sensor has been developed in a series of laboratory and engine tests to measure rotor blade arrival times. Comparisons are made with an industry standard optical blade tip timing system. The results show that it is possible to acquire high quality blade tip timing data for use in engine condition monitoring using an eddy current sensor. This sensor allows measurements to be taken that do not suffer from flow contamination and allow deployment for hotter flow environments.

The Development and Testing of a Gas Turbine Engine Foreign Object Damage (FOD) Detection System

2010 ◽  
Author(s):  
D. N. Cardwell ◽  
K. S. Chana ◽  
M. T. Gilboy
Keyword(s):  
Gas Turbine ◽  
Eddy Current ◽  
Engine Speed ◽  
Detection System ◽  
Acoustic Emissions ◽  
Gas Turbine Engine ◽  
Current Sensor ◽  
Foreign Object ◽  
Turbine Engine ◽  
Foreign Object Damage

This paper details the development of a prototype in-flight foreign object damage (FOD) detection system through various stages, resulting in a system capable of detecting objects as small as one gram (1g) mass. The system comprises an eddy current sensor based tip timing system and acoustic emissions vibration sensors controlled through a digital signal processor (DSP). QinetiQ have developed light weight, contamination-immune eddy current tip timing sensors for use in engine health management. Engine tests confirmed these sensors’ potential for detecting FOD events. FOD detection algorithms were developed and implemented in a prototype DSP that was built and tested on an uninstalled gas turbine engine. The trials showed that the prototype DSP FOD detection system could detect dynamic FOD events at full engine speed. Further work was carried out to enhance the FOD detection system, overcoming limitations in the previous system through the implementation of enhanced algorithms and its extension to accept four eddy current sensor inputs as well as a vibration signal input from an acoustic emissions (AE) sensor. An algorithm that computes engine speed from the tip timing data was also implemented to alleviate the need for a separate 1/rev signal. A number of engine trials were successfully completed in order to validate the system. The speed algorithm has been successfully validated on engine trials and comparisons with a conventional optical based 1/rev showed the DSP-generated 1/rev signals to be almost identical to the conventional system. Typically, the error was in the region of 0.03% speed. The investigations culminated in a test series designed to ascertain the system’s sensitivity to foreign object impacts. These demonstrated that the system was capable of detecting objects down to one gram (1g) mass introduced at low speed into the engine intake.

scholarly journals Wavelet Transform-Based Damage Identification in Bladed Disks and Rotating Blades

2018 ◽  
Vol 2018 ◽  
pp. 1-16
Author(s):  
P. Rajendran ◽  
N. Jamia ◽  
S. El-Borgi ◽  
M. I. Friswell
Keyword(s):  
Eddy Current ◽  
Damage Identification ◽  
Wavelet Packet ◽  
Severity Index ◽  
Current Sensor ◽  
Diagnostic Features ◽  
Blade Vibration ◽  
Rotating Blades ◽  
Bladed Disk ◽  
Eddy Current Sensor

Blade vibration and blade clearance are effective diagnostic features for the identification of blade damage in rotating machines. Blade tip-timing (BTT) is a noncontact method that is often used to monitor the vibration and clearance of blades in a rotating machinery. Standard signal processing of BTT measurements give one blade response sample per revolution of the machine which is often insufficient for the diagnosis of damage. This paper uses the raw data signals from the sensors directly and employs a wavelet energy-based mistuning index (WEBMI) to predict the presence and locations of damage in rotating blades. The Lipschitz exponent is derived from the wavelet packet coefficients and used to estimate the severity of the damage. In this study, experiments were conducted to obtain BTT measurements on rotating blades at 100 rpm using three different sensors: an active eddy current sensor, a passive eddy current sensor, and an optical sensor. In addition, hammer excitation experiments were conducted for various added mass (damage) cases to compute the damage severity for a bladed disk. To simulate the damage experimentally in the bladed disk and rotating blades, masses were added to the blades to alter their dynamics and mimic the damage. The results indicate that the WEBMI can detect the presence and location of damage in rotating blades using measurements from common BTT sensors. To check the robustness of the proposed damage severity index, the experimental results were compared with numerical simulation for the bladed disk and showed good agreement.

scholarly journals Simulating eddy current sensor outputs for blade tip timing

2018 ◽  
Vol 10 (1) ◽  
pp. 168781401774802 ◽  
Author(s):  
Nidhal Jamia ◽  
Michael I Friswell ◽  
Sami El-Borgi ◽  
Ralston Fernandes
Keyword(s):  
Eddy Current ◽  
Tip Clearance ◽  
Vibration Measurement ◽  
Current Sensor ◽  
Contactless Method ◽  
Diagnostic Features ◽  
Blade Vibration ◽  
Eddy Current Sensor ◽  
Blade Tip ◽  
Current Sensors

Blade tip timing is a contactless method used to monitor the vibration of blades in rotating machinery. Blade vibration and clearance are important diagnostic features for condition monitoring, including the detection of blade cracks. Eddy current sensors are a practical choice for blade tip timing and have been used extensively. As the data requirements from the timing measurement become more stringent and the systems become more complicated, including the use of multiple sensors, the ability to fully understand and optimize the measurement system becomes more important. This requires detailed modeling of eddy current sensors in the blade tip timing application; the current approaches often rely on experimental trials. Existing simulations for eddy current sensors have not considered the particular case of a blade rotating past the sensor. Hence, the novel aspect of this article is the development of a detailed quasi-static finite element model of the electro-magnetic field to simulate the integrated measured output of the sensor. This model is demonstrated by simulating the effect of tip clearance, blade geometry, and blade velocity on the output of the eddy current sensor. This allows an understanding of the sources of error in the blade time of arrival estimate and hence insight into the accuracy of the blade vibration measurement.

Inspection of Surface Rolled Sintered Gears using Eddy-Current Sensor

2013 ◽  
Vol 133 (5) ◽  
pp. 300-306
Author(s):  
Tsutomu Mizuno ◽  
Yuichi Asato ◽  
Sho Goto ◽  
Takashi Watanabe ◽  
Teruie Takemasu ◽  
...  
Keyword(s):  
Eddy Current ◽  
Current Sensor ◽  
Eddy Current Sensor

scholarly journals Eddy Current Sensor System for Tilting Independent In-Process Measurement of Magnetic Anisotropy

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2652
Author(s):  
Frank Wendler ◽  
Rohan Munjal ◽  
Muhammad Waqas ◽  
Robert Laue ◽  
Sebastian Härtel ◽  
...  
Keyword(s):  
Magnetic Anisotropy ◽  
Eddy Current ◽  
Digital Signal ◽  
Production Equipment ◽  
Sensor System ◽  
Current Sensor ◽  
Cold Forming ◽  
Eddy Current Sensor ◽  
Two Samples ◽  
Internal Mechanical Stress

Modern production equipment is based on the results of quality control as well as process parameters. The magnetic anisotropy of materials is closely connected to internal mechanical stress by the Villari effect, and also to hardening effects due to plastic deformations, and could therefore provide an interesting basis for process control. Nevertheless, the analysis of anisotropic properties is extremely sensitive to sensor and workpiece misalignments, such as tilting. In this work, a novel eddy current sensor system is introduced, performing a non-contact measurement of the magnetic anisotropy of a workpiece and realizing a separation and correction of tilting effects. The measurement principle is demonstrated with the example of two samples with different magnetic anisotropy values induced by cold forming. Both samples are analyzed under different tilt angles between the sensor axis and the surface of the workpiece. In this work, digital signal processing is demonstrated on the acquired raw data in order to differentiate the effects of tilt and of anisotropy, with the use of preliminary results as an example of two prepared samples.

Design and Implement of High-Accuracy On-Line Metal Thickness Measuring Instrument Based on NiosII Processor

2013 ◽  
Vol 834-836 ◽  
pp. 930-934
Author(s):  
Shou Liang Yang ◽  
Bao Liang Yang
Keyword(s):  
Eddy Current ◽  
Low Cost ◽  
High Accuracy ◽  
Resolving Power ◽  
Current Sensor ◽  
Measuring Instrument ◽  
Precision Data ◽  
Eddy Current Sensor ◽  
Metal Thickness ◽  
On Line

The paper proposes a new design of high-accuracy On-line Metal Thickness Measuring Instrument, which was based on EP2C20 series FPGA chip, through adding NiosII soft processor and other interfaces to FPGA, equipped with high precision data collection system and TFT LCD module and so on. The key hardware blocks schematics and components of the RC Oscillation Circuit,eddy current sensor Circuit,rectifier and filter Circuit,A/D converting circuit,FPGA Circuit are described,software flow charts and sample codes are given. According to practice, The measurement range of this system is 1~100 mm and the resolving power is 0.1 μm. degree of linearity is 1%, The system has many features including small volume of hardware, low cost, high detecting precision, convenient operating, high intelligent and so on, leading to broad and bright future. Key words: NiosII processor; eddy current sensor; metal thickness

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