scholarly journals Laser-Optical Blade Tip Clearance Measurement System

1981 ◽  
Vol 103 (2) ◽  
pp. 457-460 ◽  
Author(s):  
J. P. Barranger ◽  
M. J. Ford

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.

Author(s):  
Richard Grzybowski ◽  
George Foyt ◽  
Hartwig Knoell ◽  
William Atkinson ◽  
Josef Wenger

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.


2020 ◽  
Vol 53 (3-4) ◽  
pp. 339-357 ◽  
Author(s):  
Bing Yu ◽  
Hongwei Ke ◽  
Enyu Shen ◽  
Tianhong Zhang

Blade tip clearance is one of the important parameters affecting the performance, safety and stability of a gas turbine engine. However, it is difficult to measure the tip clearance in real time and accurately during the development and test process of an engine. In order to promote the development of tip clearance–measuring technology and the optimal design of the gas turbine engine, some typical measuring methods of tip clearance and a novel measuring method based on AC discharge are introduced. In this article, the significance for measuring tip clearance of an engine is illustrated first. Then, operating principles, characteristics and developments of those typical measurement approaches are introduced. After that, these methods are analyzed, and the particular characteristic of each measuring approach is summarized.


Author(s):  
A. G. Sheard ◽  
B. Killeen

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.


1997 ◽  
Vol 119 (4) ◽  
pp. 877-884 ◽  
Author(s):  
D. Mu¨ller ◽  
A. G. Sheard ◽  
S. Mozumdar ◽  
E. Johann

It is an established fact that the efficiency of a gas turbine engine has an inverse relationship with the clearance between the rotor blades and the casing (Tip Clearance, or TC). TC is an essential measurement during the testing of development engines. While commercial TC measurement systems are available, their applicability to an engine is dictated by engine size, geometry, physical accessibility, and temperature distribution around the measurement region. This paper describes the development of a TC measurement system, based on the capacitive measurement principle, which was undertaken to satisfy the application requirements of a specific class of gas turbine engines. The requirements included a relatively long and flexible cable to route the electrical signals out of the engine. The TC measurement system was successfully used during engine testing and valuable data were obtained.


2011 ◽  
Vol 2011 ◽  
pp. 1-13 ◽  
Author(s):  
A. G. Sheard

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.


Author(s):  
D. Müller ◽  
A. G. Sheard ◽  
S. Mozumdar ◽  
E. Johann

It is an established fact that the efficiency of a gas turbine engine has an inverse relationship with the clearance between the rotor blades and the casing (Tip Clearance, or TC). TC is an essential measurement during the testing of development engines. While commercial TC measurement systems are available, their applicability to an engine is dictated by engine size, geometry, physical accessibility and temperature distribution around the measurement region. This paper describes the development of a TC measurement system, based on the capacitive measurement principle, which was undertaken to satisfy the application requirements of a specific class of gas turbine engines. The requirements included a relatively long and flexible cable to route the electrical signals out of the engine. The TC measurement system was successfully used during engine testing and valuable data were obtained.


Sign in / Sign up

Export Citation Format

Share Document