Numerical Simulation of Blade Fault Signatures From Unsteady Wall Pressure Signals

1997 ◽  
Vol 119 (2) ◽  
pp. 362-369 ◽  
Author(s):  
V. Dedoussis ◽  
K. Mathioudakis ◽  
K. D. Papailiou
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Gas Turbine ◽  
Wall Pressure ◽  
Operating Point ◽  
Calculation Time ◽  
Rotating Blades ◽  
Time Signals ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine

A method for establishing signatures of faults in the rotating blades of a gas turbine compressor is presented. The method employs a panel technique for the calculation of the flow field around blade cascades, with disrupted periodicity, a situation encountered when a blade fault has occurred. From this calculation, time signals of the pressure at a location on the casing wall, facing the rotating blades, are constituted. Processing these signals, in combination with “healthy” pressure signals, allows the constitution of fault signatures. The proposed method employs geometric data, as well as data about the operating point of the engine. It gives the possibility of establishing the fault signatures without the need of performing experiments with implanted faults. The successful application of the method is demonstrated by comparison of signatures obtained by simulation to signatures derived from experiments with implanted blade faults, in an industrial gas turbine.

scholarly journals Numerical Simulation of Blade Fault Signatures From Unsteady Wall Pressure Signals

1994 ◽  
Author(s):  
V. Dedoussis ◽  
K. Mathioudakis ◽  
K. D. Papailiou
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Gas Turbine ◽  
Wall Pressure ◽  
Operating Point ◽  
Rotating Blades ◽  
Time Signals ◽  
Geometrical Data ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine

A method for establishing signatures of faults in the rotating blades of a gas turbine compressor is presented. The method employs a panel technique for the calculation of the flow field around blade cascades, with disrupted periodicity, a situation which is encountered when a blade fault has occurred. From this calculation, time signals of the pressure at a location on the casing wall, facing the rotating blades, are constituted. Processing these signals, in combination with “healthy” pressure signals allows the constitution of fault signatures. The proposed method employs geometrical data, as well as data about the operating point of the engine. It gives the possibility of establishing the fault signatures without the need of performing experiments with implanted faults. The successful application of the method is demonstrated by comparison of signatures obtained by simulation to signatures derived from experiments with implanted blade faults, in an industrial gas turbine.

Probabilistic and Numerical Modelling of a Lobed Mixer at Windmilling Conditions

2013 ◽  
Author(s):  
Maxime Lecoq ◽  
Nicholas Grech ◽  
Pavlos K. Zachos ◽  
Vassilios Pachidis
Keyword(s):  
Flow Field ◽  
Response Surface ◽  
Gas Turbine ◽  
Pressure Loss ◽  
Total Pressure ◽  
Engine Performance ◽  
Operating Conditions ◽  
Total Pressure Loss ◽  
Operating Point ◽  
Mixing Losses

Aero-gas turbine engines with a mixed exhaust configuration offer significant benefits to the cycle efficiency relative to separate exhaust systems, such as increase in gross thrust and a reduction in fan pressure ratio required. A number of military and civil engines have a single mixed exhaust system designed to mix out the bypass and core streams. To reduce mixing losses, the two streams are designed to have similar total pressures. In design point whole engine performance solvers, a mixed exhaust is modelled using simple assumptions; momentum balance and a percentage total pressure loss. However at far off-design conditions such as windmilling and altitude relights, the bypass and core streams have very dissimilar total pressures and momentum, with the flow preferring to pass through the bypass duct, increasing drastically the bypass ratio. Mixing of highly dissimilar coaxial streams leads to complex turbulent flow fields for which the simple assumptions and models used in current performance solvers cease to be valid. The effect on simulation results is significant since the nozzle pressure affects critical aspects such as the fan operating point, and therefore the windmilling shaft speeds and air mass flow rates. This paper presents a numerical study on the performance of a lobed mixer under windmilling conditions. An analysis of the flow field is carried out at various total mixer pressure ratios, identifying the onset and nature of recirculation, the flow field characteristics, and the total pressure loss along the mixer as a function of the operating conditions. The data generated from the numerical simulations is used together with a probabilistic approach to generate a response surface in terms of the mass averaged percentage total pressure loss across the mixer, as a function of the engine operating point. This study offers an improved understanding on the complex flows that arise from mixing of highly dissimilar coaxial flows within an aero-gas turbine mixer environment. The total pressure response surface generated using this approach can be used as look-up data for the engine performance solver to include the effects of such turbulent mixing losses.

scholarly journals Optimizing Automated Gas Turbine Fault Detection Using Statistical Pattern Recognition

1992 ◽  
Author(s):  
E. Loukis ◽  
K. Mathioudakis ◽  
K. Papailiou
Keyword(s):  
Decision Making ◽  
Pattern Recognition ◽  
Gas Turbine ◽  
Statistical Pattern Recognition ◽  
Dynamic Measurements ◽  
Statistical Pattern ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine ◽  
Spectral Patterns ◽  
Automated Decision Making

A method enabling the automated diagnosis of Gas Turbine Compressor blade faults, based on the principles of statistical pattern recognition is initially presented. The decision making is based on the derivation of spectral patterns from dynamic measurements data and then the calculation of discriminants with respect to reference spectral patterns of the faults while it takes into account their statistical properties. A method of optimizing the selection of discriminants using dynamic measurements data is also presented. A few scalar discriminants are derived, in such a way that the maximum available discrimination potential is exploited. In this way the success rate of automated decision making is further improved, while the need for intuitive discriminant selection is eliminated. The effectiveness of the proposed methods is demonstrated by application to data coming from an Industrial Gas Turbine while extension to other aspects of Fault Diagnosis is discussed.

Gas Turbine Compressor Dependability and Risk Mitigation Measures

2013 ◽  
Author(s):  
John R. Scheibel ◽  
Robert P. Dewey ◽  
Leonard Angello ◽  
Josh Barron
Keyword(s):  
Gas Turbine ◽  
Risk Mitigation ◽  
Acoustic Emissions ◽  
Mitigation Measures ◽  
Pressure Pulsations ◽  
Case Histories ◽  
Specific Component ◽  
Analysis And Evaluation ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine

This paper addresses recent industrial gas turbine compressor dependability issues and risk mitigation measures viewed from the end user’s perspective. Industrial reliability-availability-maintainability statistics related to power generation applications are reviewed. Several case histories with specific component issues involving blades and vanes are covered. Case histories are used to summarize field experience, engineering analysis and evaluation of related design and operating modifications as appropriate. Recent progress with setting up a field monitoring demonstration using pressure pulsations, vibration and acoustic emissions is summarized.

scholarly journals Loss in Axial Compressor Bleed Systems

2019 ◽  
Author(s):  
S. D. Grimshaw ◽  
J. Brind ◽  
G. Pullan ◽  
R. Seki
Keyword(s):  
Gas Turbine ◽  
Control Volume ◽  
Axial Compressor ◽  
Thermodynamic Cycle ◽  
Loss Coefficient ◽  
Dynamic Head ◽  
Definition Of ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine ◽  
Loss Mechanisms

Abstract Loss in axial compressor bleed systems is quantified, and the loss mechanisms identified, in order to determine how efficiency can be improved. For a given bleed air pressure requirement, reducing bleed system loss allows air to be bled from further upstream in the compressor, with benefits for the thermodynamic cycle. A definition of isentropic efficiency which includes bleed flow is used to account for this. Two cases with similar bleed systems are studied: a low-speed, single-stage research compressor and a large industrial gas turbine high-pressure compressor. A new method for characterising bleed system loss is introduced, using research compressor test results as a demonstration case. A loss coefficient is defined for a control volume including only flow passing through the bleed system. The coefficient takes a measured value of 95% bleed system inlet dynamic head, and is shown to be a weak function of compressor operating point and bleed rate, varying by ±2.2% over all tested conditions. This loss coefficient is the correct non-dimensional metric for quantifying and comparing bleed system performance. Computations of the research compressor and industrial gas turbine compressor identify the loss mechanisms in the bleed system flow. In both cases, approximately two-thirds of total loss is due to shearing of a high-velocity jet at the rear face of the bleed slot, one quarter is due to mixing in the plenum chamber and the remainder occurs in the off-take duct. Therefore, the main objective of a designer should be to diffuse the flow within the bleed slot. A redesigned bleed slot geometry is presented that achieves this objective and reduces the loss coefficient by 31%.

scholarly journals Fitting a Pitch

2009 ◽  
Vol 131 (12) ◽  
pp. 38-42 ◽  
Author(s):  
Lee S. Langston
Keyword(s):  
Gas Turbine ◽  
Airline Industry ◽  
Axial Flow ◽  
Jet Engines ◽  
Jet Engine ◽  
Rotating Blades ◽  
Fuel Savings ◽  
Turbine Efficiency ◽  
Gas Turbine Compressor ◽  
Air Carriers

This article discusses gas turbine efficiency, which is an essential but often unappreciated aspect of turbomachine design pitch. To an engineer, the pitch of a turbo machinery blade is the angle at a representative blade cross-section between the blade chord line and the plane of the blade’s rotation. An axial flow gas turbine consists of many rows of rotating blades, interspersed with rows of stationary airfoils, called vanes or stators. The gas turbine compressor (whose first row of rotating blades in a jet engine may be a fan) draws in air, which after passing through a combustor to add energy to the air flow, powers the turbine which drives the compressor. Most modern commercial jet engines are turbofan, with a front mounted fan, whose size is indicated by the bypass ratio. During the 1990s, jet engine companies developed and tested variable pitch turbofans, with cycle studies showing between 6 and 14% fuel savings. If fuel savings could spread through the airline industry, changing the pitch could lead to air carriers singing a happier tune.

scholarly journals Metallurgical Development for Added Reliability of Industrial Gas Turbine Rotating Blades

1968 ◽  
Author(s):  
F. J. Wall
Keyword(s):  
Gas Turbine ◽  
Stress Rupture ◽  
Rotating Blades ◽  
Time Stress ◽  
Corrosion Evaluation ◽  
Long Time ◽  
Industrial Gas Turbine ◽  
Microstructural Studies ◽  
Selection Of

Increased reliability of industrial gas turbine rotating blades in the hot section of turbines has been achieved by utilization of advanced metallurgical techniques. These techniques include vacuum melting master alloy heats, minimizing residual stresses in blades after machining, and increasing the quality of nondestructive inspection of blades during and after fabrication. In addition, long time stress-rupture tests, corrosion evaluation, and microstructural studies on advanced alloys have provided necessary information for selection of turbine blade alloys for future generations of turbines.

Package Design for a 5500 BHP Aeroderivative Industrial Gas Turbine

1997 ◽  
Author(s):  
Douglas L. Wenzel ◽  
Jeffrey M. Elmore
Keyword(s):  
Gas Turbine ◽  
New Product Development ◽  
Gas Generator ◽  
Package Design ◽  
Power Turbine ◽  
Total Product ◽  
Design Cycle ◽  
Management Techniques ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine

The Cooper-Bessemer Rotating Products group of Cooper Energy Services has designed an all-new industrial gas turbine / compressor package based upon the Allison Engine Company 501-KC5 gas generator with a two-stage industrial power turbine. The latest project management techniques were employed to reduce design cycle time while optimizing total product quality, manufacturability, and reliability. The resulting gas turbine / compressor package is a low-risk, technologically conservative approach, designed to avoid the problems often associated with new product development.

scholarly journals Condition Assessment of Industrial Gas Turbine Compressor Using a Drift Soft Sensor Based in Autoencoder

Sensors ◽  
2021 ◽  
Vol 21 (8) ◽  
pp. 2708
Author(s):  
Martí de Castro-Cros ◽  
Stefano Rosso ◽  
Edgar Bahilo ◽  
Manel Velasco ◽  
Cecilio Angulo
Keyword(s):  
Gas Turbine ◽  
Good Condition ◽  
Condition Assessment ◽  
Soft Sensor ◽  
Soft Sensors ◽  
Gas Turbine Compressor ◽  
Industrial Gas Turbine ◽  
Long Term Performance ◽  
Changes Over Time ◽  
Term Performance

Maintenance is the process of preserving the good condition of a system to ensure its reliability and availability to perform specific operations. The way maintenance is nowadays performed in industry is changing thanks to the increasing availability of data and condition assessment methods. Soft sensors have been widely used over last years to monitor industrial processes and to predict process variables that are difficult to measured. The main objective of this study is to monitor and evaluate the condition of the compressor in a particular industrial gas turbine by developing a soft sensor following an autoencoder architecture. The data used to monitor and analyze its condition were captured by several sensors located along the compressor for around five years. The condition assessment of an industrial gas turbine compressor reveals significant changes over time, as well as a drift in its performance. These results lead to a qualitative indicator of the compressor behavior in long-term performance.

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