Single-Coil Eddy Current Sensors and Their Application for Monitoring the Dangerous States of Gas-Turbine Engines

Abstract

The creation and exploitation of gas turbine engines (GTE) often involve two mutually exclusive tasks related to ensuring the highest reliability while achieving a good economic and environmental performance of the power plant. The value of the radial clearance between the blade tips of the compressor or turbine and the stator is a parameter that has a significant impact on the efficiency and safety of the GTE. However, the radial displacements that form tip clearances are only one of the components of the displacements made by GTE elements due to the action of power loads and thermal deformations during engines’ operation. The impact of loads in conjunction with natural aging is also the reason for the wear of the GTE’s structural elements (for example, bearing assemblies) and the loss of their mechanical strength. The article provides an overview of the methods and tools for monitoring the dangerous states of the GTE (blade tips clearances, impellers and shafts displacements, debris detecting in lubrication system) based on the single-coil eddy current sensor, which remains operational at the temperatures above 1200 °C. The examples of practical application of the systems with such sensors in bench tests of the GTE are given.

Identification of the ferromagnetic hysteresis simulation parameters using classic non-destructive testing equipment

“…Despite its relative simplicity, it conveys a large amount of information. Different configurations of ECT have already been described in the scientific literature: _ The single coil method [2]. _ The Transmitter/Receiver (TR) probe method [3].…”

Wear Diagnostics of the Thrust Bearing of NK-33 Turbo-Pump Unit on the Basis of Single-Coil Eddy Current Sensors

“…The various approaches for the diagnosis of the bearing mount assemblies state in power plants are currently known. The detection of the metal wear particles in the lubrication system of the bearing assembly [ 5 , 6 , 7 , 8 , 9 ], the acoustic or vibration signal analysis [ 10 , 11 ], the temperature measurement [ 12 , 13 ] or their combination [ 14 ] are the most popular methods among those used in the aerospace applications. At the same time considering the strict requirement from the LPRE developers of the inadmissibility of any changes in the TPU body, the application of these methods is not possible, because they all require modifying the construction of the TPU to install the appropriate sensors.…”

“…The article proposes a solution to the problem of the CJTB early wear diagnostics based on replacing the standard induction sensors of the turbo-pump rotational speed by single-coil eddy current sensors (SCECS) with sensitive elements (SE) in the form of a segment of a linear conductor [ 5 , 16 , 17 , 18 ] that constitute a separate and independent branch among the eddy current sensors used in aerospace engine building [ 19 , 20 , 21 , 22 ]. The SCECS provide the monitoring of the axial displacement of the shaft in the CJTB, which characterizes the bearing wear.…”

High Temperature Magnetic Sensors

“…Capacity probes are mainly used for this purpose, but several measurement solutions based on active eddy-current principle were proposed, e.g. [9][10][11]. Some interesting sensor designs in low temperature co-fired ceramics (LTCC) technology were also presented [12][13][14].…”