On the development of a magnetoresistive sensor for blade tip timing and blade tip clearance measurement systems

2014 ◽  
Author(s):  
R. Tomassini ◽  
G. Rossi ◽  
J-F. Brouckaert
Keyword(s):  
Tip Clearance ◽  
Measurement Systems ◽  
Magnetoresistive Sensor ◽  
Blade Tip ◽  
Blade Tip Clearance

Blade Tip Clearance Measurement Systems for High Speed Turbomachinery Applications and the Potential for Blade Tip Timing Applications

2020 ◽  
Author(s):  
Jack David Stubbs ◽  
Muhammad Arslan Shahid
Keyword(s):  
Measurement Uncertainty ◽  
High Speed ◽  
Radial Displacement ◽  
Measurement Techniques ◽  
Test System ◽  
Tip Clearance ◽  
Optical Systems ◽  
Measurement Systems ◽  
Blade Tip ◽  
Blade Tip Clearance

Abstract As turbomachinery OEMs focus efforts to further increase reliability, power and efficiencies, the running clearance between blade tips and stator continue to be of the utmost importance. This paper investigates the capability of capacitive tip clearance systems to perform individual blade tip clearance measurements on high speed rotors of up to 90,000rpm. A rotor was designed using finite element analysis; unique blade responses have been predicted. The objective of this investigation was to consider two different approaches to the application of blade tip clearance measurements and the system requirements to accurately measure low levels of radial displacement of a target rotating between 1,000rpm and 90,000rpm. The first uses the standard approach with passive probes and the second, a new technique using active probes that have demonstrated bandwidths of 1.2MHz and increased measuring range with a lower level of measurement uncertainty. Both systems’ approaches are compared, and their capabilities are evaluated for high-speed applications. The higher bandwidth capabilities of the latter system, combined with smaller sensor diameters, produces comparable signal rise times to the optical systems used in blade tip timing measurements. The difference in approach offers the potential of contamination resistant sensors for long term blade tip timing applications and measurement probes that do not require cooling systems to withstand higher temperature applications. The use of different probe configurations, in a number of applications, has demonstrated a two-fold improvement in the measurement range whilst producing lower levels of noise and uncertainty when applied to blade targets made from composites, aluminium and nickel-alloy materials. The measurement data presented includes individual blade’s radial displacement, identified shaft axial displacement, effects of resonance in the test system and the identification of the main drivers of measurement uncertainty along with an achievable value. The capacitive measurement systems’ performance for blade tip clearance is analysed and reported. The capability to perform other measurement techniques such as blade tip timing with a dual use measurement probe is also analysed and reported. This is done by correlating measurement results between the capacitive systems with that of a repeat measurement of the same target using an optical BTT system.

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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