scholarly journals An Optical Fiber Measurement System for Blade Tip Clearance of Engine

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Jia Binghui ◽  
He Lei
Keyword(s):  
Optical Fiber ◽  
Measurement System ◽  
High Speed ◽  
Dynamic Performance ◽  
Measurement Range ◽  
Tip Clearance ◽  
Processing Unit ◽  
Blade Tip ◽  
Optical Fiber Measurement ◽  
Blade Tip Clearance

The benefits of reducing the tip clearance have been receiving many scholars’ attention all the time, which bring turbine efficiency increasing, emissions reduction, payloads increasing, and mission range abilities extension. In order to gain the blade tip clearance dynamically, a prototype optical fiber measurement system was built and tested based on the rotor test rig. The optical fiber tip clearance measurement system consists of the reflective intensity-modulated optical fiber bundle (sensor), main signal processing unit, high-speed data acquisition card, and a computer. The static performance and dynamic performance experiments were conducted to verify the performance of the system we designed. In addition, the results show that the accuracy of the system is 25 μm or better; the stability of the measurement system was evaluated in room temperature. The clearance measurement range is about 5 mm, and sensitivity of the sensor is 0.0733/mm. Furthermore, the typical tip clearance dynamic measurement experiment results show that the system has good dynamic response characteristics as well. The system will provide a new tool for engine health monitoring or fast active tip clearance control.

Optical fiber measurement system for 3-D variation of turbine blade tip clearance

2018 ◽  
Vol 26 (7) ◽  
pp. 1578-1587 ◽  
Author(s):  
张小栋 ZHANG Xiao-dong ◽  
吴 冰 WU Bing ◽  
谢思莹 XIE Si-ying
Keyword(s):  
Optical Fiber ◽  
Turbine Blade ◽  
Measurement System ◽  
Tip Clearance ◽  
Blade Tip ◽  
Optical Fiber Measurement ◽  
Blade Tip Clearance

scholarly journals Measuring Rotor and Blade Dynamics Using an Optical Blade Tip Sensor

1990 ◽  
Author(s):  
Harold R. Simmons ◽  
Douglas L. Michalsky ◽  
Kenneth E. Brewer ◽  
Anthony J. Smalley
Keyword(s):  
Measurement System ◽  
High Speed ◽  
High Performance ◽  
Optical Measurement ◽  
Tip Clearance ◽  
Calibration Data ◽  
Rotor Vibration ◽  
Position Sensing ◽  
Blade Tip ◽  
Blade Tip Clearance

This paper describes an optical measurement system for monitoring combustion turbine blade tips. The sensor measures distance to a blade tip using triangulation of reflected laser light. The system accomplishes triangulation using an optical position sensing device and high speed data acquisition. In this way, it is able to monitor not only average and minimum blade tip clearances, but to monitor the variations of individual blade tip clearances. By appropriate signal processing, it is possible to determine rotor vibration at the probe axial location, variations in shaft DC position, transient losses in blade tip clearance, the potential for tip and seal rubs, vibrations of individual blades in the tangential direction, and rotor torsional vibration at the probe location. Some aspects of blade and torsional vibrations would require more than one probe. The paper presents static calibration data for the measurement system, showing its degree of linearity and range. The paper also presents data obtained on a dynamic blade test rig with tip passing speeds and blade widths comparable to those encountered in high performance industrial combustion turbines. Data from this rig have been processed to show rotor vibration, shift in shaft average position, blade-to-blade tip clearance variation, and variation with speed of minimum blade tip clearance. The measurement system is designed to produce data suitable for use in the monitoring of advanced combustion turbine durability and the diagnosis of turbine functional problems, static and dynamic.

A Blade by Blade Tip Clearance Measurement System for Gas Turbine Applications

1994 ◽  
Author(s):  
A. G. Sheard ◽  
B. Killeen
Keyword(s):  
Gas Turbine ◽  
Measurement System ◽  
System Reliability ◽  
System Performance ◽  
Tip Clearance ◽  
Test Facility ◽  
Hostile Environment ◽  
Reliable Measurement ◽  
Blade Tip ◽  
Blade Tip Clearance

It is difficult to make a reliable measurement of running clearance in the hostile environment over the blading of a modern gas turbine. When engine manufacturers require the measurement to be made over every blade during live engine tests, system reliability, ruggedness and ease of operation are of primary importance. This paper describes a tip clearance measurement system that can measure clearance over every blade around a rotor. The measurement system concept is presented, and the system design described in detail. Commissioning of the measurement system on a compressor test facility, and the results obtained are discussed. An analysis of system performance during the commissioning trials concludes the paper.

scholarly journals Blade by Blade Tip Clearance Measurement

2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
A. G. Sheard
Keyword(s):  
High Temperature ◽  
Gas Turbine ◽  
Measurement System ◽  
Measurement Techniques ◽  
Tip Clearance ◽  
Initial Development ◽  
Real World Applications ◽  
Blade Tip ◽  
Capacitance Probe ◽  
Blade Tip Clearance

This paper describes a capacitance-based tip clearance measurement system which engineers have used in the most demanding turbine test applications. The capacitance probe has survived extended use in a major European gas turbine manufacturer's high-temperature demonstrator unit, where it functioned reliably at a turbine entry temperature in excess of 1800 degrees Kelvin. This paper explores blade by blade tip clearance measurement techniques and examines probe performance under laboratory conditions in support of high-temperature installations. The paper outlines the blade by blade tip clearance measurement technique and describes the experimental facility used to study tip clearance measurement. The paper also fully describes the method used to calibrate the measurement system in order to ascertain measurement accuracy. The paper clarifies how the practical problems were overcome associated with making blade by blade tip clearance measurements in both compressor and turbine environments. Since its initial development, gas turbine development programmes have routinely used the clearance measurement system. The inherent robustness of the system has resulted in reliable in-service measurement of clearance in real world applications.

scholarly journals High-Precision Extraction Method for Blade Tip-Timing Signal with Eddy Current Sensor

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Ji-wang Zhang ◽  
Ke-qin Ding ◽  
Guang Chen
Keyword(s):  
Measurement Error ◽  
Eddy Current ◽  
Background Noise ◽  
High Speed ◽  
Ensemble Empirical Mode Decomposition ◽  
Tip Clearance ◽  
Mode Decomposition ◽  
Blade Tip ◽  
The Asymmetry ◽  
Blade Tip Clearance

Online monitoring of high-speed rotating blades has always been a hot topic. Of the various methods, the blade tip timing (BTT) technique, based on eddy current sensors, is considered to be the most promising. However, BTT signals are easily influenced by various factors, which means that the accurate extraction of BTT signals remains a challenge. To try to solve this problem, the causes of measurement error were analyzed. The three main reasons for the error were established: the variation in blade tip clearance, the interference of background noise, and the asymmetry of the blade tip shape. Further, pertinent improvement methods were proposed, and a compensation method was proposed for the errors caused by the variation of tip clearance. A new denoising and shaping algorithm based on ensemble empirical mode decomposition (EEMD) was introduced for the errors caused by background noise. Additionally, an optimal installation position of the sensor was also proposed for the errors caused by the asymmetry of the blade tip shape. Finally, simulations and experiments were used to demonstrate the improved methodology. The results show that the measurement error on vibration amplitude and vibration frequency using the proposed method is less than 2.89% and 0.17%, respectively, which is much lower than the traditional method (24.44% and 0.39%, respectively).

scholarly journals Microwave Blade Tip Clearance Measurement System

1996 ◽  
Author(s):  
Richard Grzybowski ◽  
George Foyt ◽  
Hartwig Knoell ◽  
William Atkinson ◽  
Josef Wenger
Keyword(s):  
Gas Turbine ◽  
Measurement System ◽  
Ceramic Materials ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Phase Measurements ◽  
Blade Tip ◽  
Clearance Control ◽  
Blade Tip Clearance

This paper describes the development of a Microwave Tip Clearance Measurement System for use in the gas turbine environment Applications for this sensor include basic tip clearance measurements, seal wear measurement and active blade tip clearance control in gas turbine engines. The system being developed was designed for useful operation to temperatures exceeding 1093°F, since only ceramic materials are directly exposed in the gas path. Other advantages of this microwave approach to blade tip clearance sensing include the existence of an inherent self-calibration in the sensor that permits accurate operation despite temperature variations and possible abrasion by the rotating blades. Earlier experiments designed to simulate this abrasion of the sensor head indicated that rubs as deep as 1 mm (40 mils) were easily tolerated. In addition, unlike methods based upon phase measurements, this method is very insensitive to cable vibration and length variations. Finally, this microwave technique is expected to be insensitive to fuel and other engine contamination, since it is based on the measurement of resonant frequencies, which are only slightly affected by moderate values of loss due to contamination.

scholarly journals Laser-Optical Blade Tip Clearance Measurement System

1981 ◽  
Vol 103 (2) ◽  
pp. 457-460 ◽  
Author(s):  
J. P. Barranger ◽  
M. J. Ford
Keyword(s):  
Gas Turbine ◽  
Measurement System ◽  
Optical Measurement ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Blade Tip ◽  
Graphic Terminal ◽  
Blade Tip Clearance

The need for blade tip clearance instrumentation has been intensified recently by advances in technology of gas turbine engines. A new laser-optical measurement system has been developed to measure single blade tip clearances and average blade tip clearances between a rotor and its gas path seal in rotating component rigs and complete engines. The system is applicable to fan, compressor and turbine blade tipe clearance measurements. The engine mounted probe is particularly suitable for operation in the extreme turbine environment. The measurement system consists of an optical subsystem, an electronic subsystem and a computing and graphic terminal. Bench tests and environmental tests were conducted to confirm operation at temperatures, pressures, and vibration levels typically encountered in an operating gas turbine engine.

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