scholarly journals Estimation of Performance Parameters of Turbine Engine Components Using Experimental Data in Parametric Uncertainty Conditions

2019 ◽  
Author(s):  
Olexandr Khustochka ◽  
Sergiy Yepifanov ◽  
Roman Zelenskyi ◽  
Radoslaw Przysowa
Keyword(s):  
Experimental Data ◽  
Path Analysis ◽  
Measurement Errors ◽  
Dynamic Models ◽  
A Priori ◽  
Estimation Method ◽  
Parametric Uncertainty ◽  
Performance Parameters ◽  
Turbine Engine ◽  
Engine Components

Gas Path Analysis and matching turbine engine models to experimental data are inverse problems of mathematical modelling which are characterized by parametric uncertainty. This results from the fact that the number of measured parameters is significantly lower than the number of components’ performance parameters needed to describe the real engine. In these conditions, even small measurement errors can result in a high variation of results, and obtained efficiency, loss factors etc. can appear out of the physical range. The current methods of engine model identification have developed considerably to provide stable, precise and physically adequate solutions. Presented in this work is an estimation method of engine components’ parameters based on multi-criteria identification which provides stable estimations of parameters and their confidence intervals with the known measurement errors. A priori information about the engine, its parameters and performance is used directly in the regularised identification procedure. The mathematical basis for this approach is the fuzzy sets theory. Forming objective functions and scalar convolutions synthesis of these functions is used to estimate gas-path components’ parameters. A comparison of the proposed approach with traditional methods showed that its main advantage is high stability of estimation in the parametric uncertainty conditions. Regularization reduces scattering, excludes incorrect solutions which do not correspond to a priori assumptions, and also helps to implement the Gas Path Analysis at the limited number of measured parameters. The method can be used for matching thermodynamic models to experimental data, Gas Path Analysis and also adapting dynamic models for the needs of the engine control system.

scholarly journals Estimation of performance parameters of turbine engine components using experimental data in parametric uncertainty conditions

2019 ◽  
Vol 304 ◽  
pp. 03003
Author(s):  
Olexandr Khustochka ◽  
Sergey Chernysh ◽  
Sergiy Yepifanov ◽  
Mykhaylo Ugryumov ◽  
Radoslaw Przysowa
Keyword(s):  
Experimental Data ◽  
Path Analysis ◽  
Measurement Errors ◽  
A Priori ◽  
Parametric Uncertainty ◽  
Performance Parameters ◽  
A Priori Information ◽  
Turbine Engine ◽  
Priori Information ◽  
Engine Components

Gas Path Analysis and matching turbine engine models to experimental data are inverse problems of mathematical modelling which are characterized by parametric uncertainty. It results from the fact that the number of measured parameters is significantly less than the number of components’ performance parameters needed to describe the real engine. Inthese conditions, even small measurement errors can result in a high variation of results, and obtained efficiency, lossfactors etc. can appear out of the physical range. The paper presents new method for setting a priori information about the engine and its performance in view of fuzzy sets, forming objective functions and scalar convolutions synthesis of these functions to estimate gas-path components’ parameters. The comparison of the proposed approach with traditional methods showed that its main advantage is high stability of estimation in the parametric uncertainty conditions. It reduces scattering, excludes incorrect solutions which do not correspond to a priori assumptions, and also helps to implement the Gas Path Analysis at the limited number of measured parameters.

scholarly journals Estimation of Performance Parameters of Turbine Engine Components Using Experimental Data in Parametric Uncertainty Conditions

Aerospace ◽  
2020 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Olexandr Khustochka ◽  
Sergiy Yepifanov ◽  
Roman Zelenskyi ◽  
Radoslaw Przysowa
Keyword(s):  
Experimental Data ◽  
Path Analysis ◽  
Measurement Errors ◽  
Dynamic Models ◽  
A Priori ◽  
Parametric Uncertainty ◽  
Diagnostic Systems ◽  
Identification Procedure ◽  
Mathematical Basis ◽  
Engine Components

Zero-dimensional models based on the description of the thermo-gas-dynamic process are widely used in the design of engines and their control and diagnostic systems. The models are subjected to an identification procedure to bring their outputs as close as possible to experimental data and assess engine health. This paper aims to improve the stability of engine model identification when the number of measured parameters is small, and their measurement error is not negligible. The proposed method for the estimation of engine components’ parameters, based on multi-criteria identification, provides stable estimations and their confidence intervals within known measurement errors. A priori information about the engine, its parameters and performance is used directly in the regularized identification procedure. The mathematical basis for this approach is the fuzzy sets theory. Synthesis of objective functions and subsequent scalar convolutions of these functions are used to estimate gas-path components’ parameters. A comparison with traditional methods showed that the main advantage of the proposed approach is the high stability of estimation in the parametric uncertainty conditions. Regularization reduces scattering, excludes incorrect solutions that do not correspond to a priori assumptions and also helps to implement the gas path analysis with a limited number of measured parameters. The method can be used for matching thermodynamic models to experimental data, gas path analysis and adapting dynamic models to the needs of the engine control system.

scholarly journals Study of Design Modification Effects through Performance Analysis of a Legacy Gas Turbine Engine

2020 ◽  
Author(s):  
Gantayata Gouda ◽  
Balaji Sankar ◽  
Venkat Iyengar ◽  
Jana Soumendu
Keyword(s):  
Experimental Data ◽  
Simulation Model ◽  
Estimation Method ◽  
Critical Parameters ◽  
Aircraft Engines ◽  
Performance Parameters ◽  
Nozzle Throat ◽  
Design Modification ◽  
Turbine Engine ◽  
Jet Nozzle

Modifications to the critical parameters, such as the exhaust nozzle area, are sometimes done during maintenance of aircraft engines. These modifications are done either to increase the design thrust or to compensate for the reduction of thrust due to leakage in the variable area jet nozzle. There is a trade-off between several performance parameters when such critical parameters are changed during maintenance. A tuned aerothermodynamic simulation model that agrees well with the experimental data from the original engine is required to study the effect of these changes. In the present work, a multipoint map scaling approach and a parameter estimation method are used to develop a simulation model that agrees well with the experimental data from the original turbojet engine. The design modifications are then incorporated in the model, and the effect of the modification on the various performance parameters is studied. The effect of leakage in the nozzle flaps and the corresponding reduction required in the nozzle throat area are calculated. It is shown that the tuned model developed with experimental testbed data enables the identification of ancillary effects of a change in a design parameter, such as the nozzle throat area.

Dynamic Traffic Flow Model for Travel Time Estimation

2015 ◽  
Vol 2526 (1) ◽  
pp. 70-78 ◽  
Author(s):  
Ting Yi ◽  
Billy M. Williams
Keyword(s):  
Fixed Point ◽  
Travel Time ◽  
Traffic Flow ◽  
Measurement Errors ◽  
Flow Model ◽  
Dynamic Models ◽  
Estimation Method ◽  
Dynamic Traffic ◽  
Traffic Flow Model ◽  
Point Detector

Travel time, as a fundamental measurement for intelligent transportation systems, is becoming increasingly important. Because of the wide deployment of fixed-point detectors on freeways, if travel time can be accurately estimated from point detector data, the indirect estimation method is cost-effective and widely applicable. This paper presents a modified dynamic traffic flow model for accurately estimating the travel time of freeway links under transition and congestion conditions with fixed-point detector data. The modified estimation model is based on a thorough analysis of the dynamic traffic flow model. The applications and the limitations of the model are analyzed for theory, equation derivation, and modifications. Through a simulation study and real traffic data, the (modified) dynamic models are compared according to performance measurements. A comparison of the estimated results and measurement errors shows the accuracy of the modified dynamic model for estimating the travel times of freeway links under transition and congestion traffic conditions.

scholarly journals Weighed ranking of aprioristic and experimental data in control system functioning efficiency estimation problem with Pascal-distributed number of tests

2020 ◽  
pp. 39-47
Author(s):  
Vladimir Arseniev ◽  
Anatolij Khomonenko ◽  
Andrei Yadrenkin
Keyword(s):  
Experimental Data ◽  
Control System ◽  
Functional Dependence ◽  
A Priori ◽  
Real Life ◽  
Estimation Method ◽  
Estimation Accuracy ◽  
Efficiency Estimation ◽  
System Functioning ◽  
Priori Information

Introduction: In order to steadily estimate the efficiency of control systems for new objects, a great number of prototypes should be tested, which is not always possible in practice. The estimation quality can be improved by joint processing of the a priori information you have before the tests by analyzing certain indicators, and the data obtained from the tests. To estimate the efficiency a posteriori, taking into account both the a priori knowledge and the test results, you have to find their functional dependence on each of them, and specify the parameters of this dependence. Purpose: Integrated processing of the results from both aprioristic and experimental research of a control system, and obtaining posterior estimations of the efficiency indices. Results: A control system efficiency estimation method is proposed, which integrates the aprioristic and experimental estimations of the efficiency indices obtained a priori and during a limited number of tests of system prototypes. It can be used when the results of aprioristic research and the tests are presented by point estimations of the efficiency indices, and the most common methods are difficult to apply. We present analytical expressions for posterior estimation of the probability that the system will perform its task, along with the indicators which are used to study the influence of the aprioristic information on the estimation accuracy and number of tests. The working capacity of the method is illustrated by a real-life example. This approach, unlike others, takes into account how close the aprioristic estimations are to the experimental ones. Practical relevance: The proposed approach is universal enough, as it allows you to integrate the information obtained at various stages of studying the system, and essentially improve the efficiency estimation accuracy, specifying the gain in the number of tests in all the cases when the aprioristic research results are in consonance with the experimental data.

Flexible manufacturing in repair of gas turbine engine components

1992 ◽  
Author(s):  
KIRK D ◽  
ANDREW VAVRECK ◽  
ERIC LITTLE ◽  
LESLIE JOHNSON ◽  
BRETT SAYLOR
Keyword(s):  
Gas Turbine ◽  
Flexible Manufacturing ◽  
Gas Turbine Engine ◽  
Turbine Engine ◽  
Engine Components

TIMETAL 829

Alloy Digest ◽  
2001 ◽  
Vol 50 (8) ◽  
Keyword(s):  
Fracture Toughness ◽  
Titanium Alloy ◽  
High Temperature ◽  
High Strength ◽  
Heat Treating ◽  
High Temperature Alloy ◽  
Turbine Engine ◽  
Major Application ◽  
Alpha Titanium ◽  
Engine Components

Abstract TIMETAL 829 is a Ti-5.5Al-3.5Sn-3Zr-1Nb-0.25Mo-0.3Si near-alpha titanium alloy that is weldable and has high strength and is a creep resistant high temperature alloy. The major application is as gas turbine engine components. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness, creep, and fatigue. It also includes information on forming and heat treating. Filing Code: TI-118. Producer or source: Timet.

Life assessment of a high temperature probe designed for performance evaluation and health monitoring of an aero gas turbine engine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Benny George ◽  
Nagalingam Muthuveerappan
Keyword(s):  
Performance Evaluation ◽  
Gas Turbine ◽  
Health Monitoring ◽  
Gas Turbine Engine ◽  
Life Assessment ◽  
Exhaust Gas ◽  
Cycle Fatigue ◽  
Creep Life ◽  
Turbine Engine ◽  
Engine Components

AbstractTemperature probes of different designs were widely used in aero gas turbine engines for measurement of air and gas temperatures at various locations starting from inlet of fan to exhaust gas from the nozzle. Exhaust Gas Temperature (EGT) downstream of low pressure turbine is one of the key parameters in performance evaluation and digital engine control. The paper presents a holistic approach towards life assessment of a high temperature probe housing thermocouple sensors designed to measure EGT in an aero gas turbine engine. Stress and vibration analysis were carried out from mechanical integrity point of view and the same was evaluated in rig and on the engine. Application of 500 g load concept to clear the probe design was evolved. The design showed strength margin of more than 20% in terms of stress and vibratory loads. Coffin Manson criteria, Larsen Miller Parameter (LMP) were used to assess the Low Cycle Fatigue (LCF) and creep life while Goodman criteria was used to assess High Cycle Fatigue (HCF) margin. LCF and HCF are fatigue related damage from high frequency vibrations of engine components and from ground-air-ground engine cycles (zero-max-zero) respectively and both are of critical importance for ensuring structural integrity of engine components. The life estimation showed LCF life of more than 4000 mission reference cycles, infinite HCF life and well above 2000 h of creep life. This work had become an integral part of the health monitoring, performance evaluation as well as control system of the aero gas turbine engine.

Life assessment of a high temperature probe designed for performance evaluation and health monitoring of an aero gas turbine engine

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Benny George ◽  
Nagalingam Muthuveerappan
Keyword(s):  
Performance Evaluation ◽  
Gas Turbine ◽  
Health Monitoring ◽  
Gas Turbine Engine ◽  
Life Assessment ◽  
Exhaust Gas ◽  
Cycle Fatigue ◽  
Creep Life ◽  
Turbine Engine ◽  
Engine Components

Abstract Temperature probes of different designs were widely used in aero gas turbine engines for measurement of air and gas temperatures at various locations starting from inlet of fan to exhaust gas from the nozzle. Exhaust Gas Temperature (EGT) downstream of low pressure turbine is one of the key parameters in performance evaluation and digital engine control. The paper presents a holistic approach towards life assessment of a high temperature probe housing thermocouple sensors designed to measure EGT in an aero gas turbine engine. Stress and vibration analysis were carried out from mechanical integrity point of view and the same was evaluated in rig and on the engine. Application of 500 g load concept to clear the probe design was evolved. The design showed strength margin of more than 20% in terms of stress and vibratory loads. Coffin Manson criteria, Larsen Miller Parameter (LMP) were used to assess the Low Cycle Fatigue (LCF) and creep life while Goodman criteria was used to assess High Cycle Fatigue (HCF) margin. LCF and HCF are fatigue related damage from high frequency vibrations of engine components and from ground-air-ground engine cycles (zero-max-zero) respectively and both are of critical importance for ensuring structural integrity of engine components. The life estimation showed LCF life of more than 4000 mission reference cycles, infinite HCF life and well above 2000 h of creep life. This work had become an integral part of the health monitoring, performance evaluation as well as control system of the aero gas turbine engine.

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