Blade tip clearance measurement of the turbine engines based on a multi-mode fiber coupled laser ranging system

2014 ◽  
Vol 85 (11) ◽  
pp. 115105 ◽  
Author(s):  
Haotian Guo ◽  
Fajie Duan ◽  
Guoxiu Wu ◽  
Jilong Zhang
Keyword(s):  
Tip Clearance ◽  
Turbine Engines ◽  
Laser Ranging ◽  
Blade Tip ◽  
Multi Mode ◽  
Blade Tip Clearance

scholarly journals New Sensors and Techniques for the Structural Health Monitoring of Propulsion Systems

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Mark Woike ◽  
Ali Abdul-Aziz ◽  
Nikunj Oza ◽  
Bryan Matthews
Keyword(s):  
Structural Health Monitoring ◽  
Health Monitoring ◽  
Crack Detection ◽  
Rotating Disk ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Structural Health ◽  
Major Interest ◽  
Blade Tip ◽  
Blade Tip Clearance

The ability to monitor the structural health of the rotating components, especially in the hot sections of turbine engines, is of major interest to aero community in improving engine safety and reliability. The use of instrumentation for these applications remains very challenging. It requires sensors and techniques that are highly accurate, are able to operate in a high temperature environment, and can detect minute changes and hidden flaws before catastrophic events occur. The National Aeronautics and Space Administration (NASA), through the Aviation Safety Program (AVSP), has taken a lead role in the development of new sensor technologies and techniques for the in situ structural health monitoring of gas turbine engines. This paper presents a summary of key results and findings obtained from three different structural health monitoring approaches that have been investigated. This includes evaluating the performance of a novel microwave blade tip clearance sensor; a vibration based crack detection technique using an externally mounted capacitive blade tip clearance sensor; and lastly the results of using data driven anomaly detection algorithms for detecting cracks in a rotating disk.

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 A review of blade tip clearance–measuring technologies for gas turbine engines

2020 ◽  
Vol 53 (3-4) ◽  
pp. 339-357 ◽  
Author(s):  
Bing Yu ◽  
Hongwei Ke ◽  
Enyu Shen ◽  
Tianhong Zhang
Keyword(s):  
Gas Turbine ◽  
Measuring Method ◽  
Gas Turbine Engine ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Blade Tip ◽  
Safety And Stability ◽  
Blade Tip Clearance

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.

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.

Microwave Blade Tip Clearance Measurements: Principles, Current Practices and Future Opportunities

2012 ◽  
Author(s):  
Alexander Maslovskiy ◽  
Mikhail Bakulin ◽  
Maksim Snitko
Keyword(s):  
Laboratory Tests ◽  
Combustion Products ◽  
Tip Clearance ◽  
Turbine Engines ◽  
Microwave Measurement ◽  
Gas Turbine Engines ◽  
Measurement Systems ◽  
Microwave Sensor ◽  
Blade Tip ◽  
Blade Tip Clearance

This article is devoted to the principles of construction of the microwave tip clearance measurement system in gas turbine engines and describes a microwave sensor that designed to operate in temperatures up to 1700C with a resolution of 0.05 mm. The sensor can effectively operate in dirty environments and has the ability to see through oil, combustion products, and other common contaminants. Also the article is devoted to the use of microwave measurement systems to solve other practical problems (measurements tip-timing, vibration, pressure and etc). The main applications of these systems are discussed on the basis of the plant tests and laboratory tests of aircraft turbine engines.

scholarly journals Creep-Based Reliability Evaluation of Turbine Blade-Tip Clearance with Novel Neural Network Regression

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3552 ◽  
Author(s):  
Chun-Yi Zhang ◽  
Jing-Shan Wei ◽  
Ze Wang ◽  
Zhe-Shan Yuan ◽  
Cheng-Wei Fei ◽  
...  
Keyword(s):  
Neural Network ◽  
High Pressure ◽  
Reliability Analysis ◽  
Response Surface ◽  
Response Surface Method ◽  
Tip Clearance ◽  
Strong Nonlinearity ◽  
Surface Method ◽  
Blade Tip ◽  
Blade Tip Clearance

To reveal the effect of high-temperature creep on the blade-tip radial running clearance of aeroengine high-pressure turbines, a distributed collaborative generalized regression extremum neural network is proposed by absorbing the heuristic thoughts of distributed collaborative response surface method and the generalized extremum neural network, in order to improve the reliability analysis of blade-tip clearance with creep behavior in terms of modeling precision and simulation efficiency. In this method, the generalized extremum neural network was used to handle the transients by simplifying the response process as one extremum and to address the strong nonlinearity by means of its nonlinear mapping ability. The distributed collaborative response surface method was applied to handle multi-object multi-discipline analysis, by decomposing one “big” model with hyperparameters and high nonlinearity into a series of “small” sub-models with few parameters and low nonlinearity. Based on the developed method, the blade-tip clearance reliability analysis of an aeroengine high-pressure turbine was performed subject to the creep behaviors of structural materials, by considering the randomness of influencing parameters such as gas temperature, rotational speed, material parameters, convective heat transfer coefficient, and so forth. It was found that the reliability degree of the clearance is 0.9909 when the allowable value is 2.2 mm, and the creep deformation of the clearance presents a normal distribution with a mean of 1.9829 mm and a standard deviation of 0.07539 mm. Based on a comparison of the methods, it is demonstrated that the proposed method requires a computing time of 1.201 s and has a computational accuracy of 99.929% over 104 simulations, which are improvements of 70.5% and 1.23%, respectively, relative to the distributed collaborative response surface method. Meanwhile, the high efficiency and high precision of the presented approach become more obvious with the increasing simulations. The efforts of this study provide a promising approach to improve the dynamic reliability analysis of complex structures.

Turbine Blade Tip Clearance Measurement Instrumentation

2007 ◽  
Author(s):  
Eric B. Holmquist ◽  
Peter L. Jalbert
Keyword(s):  
Control System ◽  
Real Time ◽  
Tip Clearance ◽  
Engine Control ◽  
Operating Characteristics ◽  
Static Structure ◽  
Engine Operation ◽  
Area Of Interest ◽  
Blade Tip ◽  
Blade Tip Clearance

New and future gas turbine engines are being required to provide greater thrust with improved efficiency, while simultaneously reducing life cycle operating costs. Improved component capabilities enable active control methods to provide better control of engine operation with reduced margin. One area of interest is a means to assess the relative position of rotating machinery in real-time, in particular hot section turbo machinery. To this end, Hamilton Sundstrand is working to develop a real-time means to monitor blade position relative to the engine static structure. This approach may yield other engine operating characteristics useful in assessing component health, specifically measuring blade tip clearance, time-of-arrival, and other parameters. UTC is leveraging its many years of experience with engine control systems to develop a microwave-based sensing device, applicable to both military and commercial engines. The presentation will discuss a hot section engine demonstration of a blade position monitoring system and the control system implications posed by a microwave-based solution. Considerations necessary to implement such a system and the challenges associated with integrating a microwave-based sensor system into an engine control system are discussed.

scholarly journals Influence of Large Relative Tip Clearances for a Micro Radial Fan and Design Guidelines for Increased Efficiency

2020 ◽  
Author(s):  
Patrick H. Wagner ◽  
Jan Van herle ◽  
Lili Gu ◽  
Jürg Schiffmann
Keyword(s):  
Pressure Rise ◽  
Leading Edge ◽  
High Sensitivity ◽  
Design Guidelines ◽  
Tip Clearance ◽  
Small Scale ◽  
Blade Tip ◽  
Dynamics Simulations ◽  
Experimental Findings ◽  
Blade Tip Clearance

Abstract The blade tip clearance loss was studied experimentally and numerically for a micro radial fan with a tip diameter of 19.2mm. Its relative blade tip clearance, i.e., the clearance divided by the blade height of 1.82 mm, was adjusted with different shims. The fan characteristics were experimentally determined for an operation at the nominal rotational speed of 168 krpm with hot air (200 °C). The total-to-total pressure rise and efficiency increased from 49 mbar to 68 mbar and from 53% to 64%, respectively, by reducing the relative tip clearance from 7.7% to the design value of 2.2%. Single and full passage computational fluid dynamics simulations correlate well with these experimental findings. The widely-used Pfleiderer loss correlation with an empirical coefficient of 2.8 fits the numerical simulation and the experiments within +2 efficiency points. The high sensitivity to the tip clearance loss is a result of the design specific speed of 0.80, the highly-backward curved blades (17°), and possibly the low Reynolds number (1 × 105). The authors suggest three main measures to mitigate the blade tip clearance losses for small-scale fans: (1) utilization of high-precision surfaced-grooved gas-bearings to lower the blade tip clearance, (2) a mid-loaded blade design, and (3) an unloaded fan leading edge to reduce the blade tip clearance vortex in the fan passage.

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