Diagnosis of Turbine Engine Transient Performance With Model-Based Parameter Estimation Techniques

Author(s):  
Jeff W. Bird ◽  
Howard M. Schwartz

This review surveys knowledge needed to develop an improved method of modelling the dynamics of gas turbine performance for fault diagnosis applications. Aerothermodynamic and control models of gas turbine processes are examined as complementary to models derived directly from test data. Extensive, often proprietary data are required for physical models of components, while system identification (SI) methods need data from specially-designed tests. Current methods are limited in: tuning models to test data, non-linear effects, component descriptions in SI models, robustness to noise, and inclusion of control systems and actuators. Conclusions are drawn that SI models could be formulated, with parameters which describe explicitly the functions of key engine components, to offer improved diagnostic capabilities.

Author(s):  
J. R. Palmer ◽  
Yong-Gen Gu

This paper presents a computer model called ‘TURBOTEST’ which is applicable both to analysis of gas turbine engine rig tests and to simulation of engine steady-state performance. As with the earlier ‘TURBOFLEXI’ model a wide range of gas turbine engines can be simulated, using any kind of hydrocarbon fuel, and allowing for chemical dissociation of the gas, and for the effect of air humidity. In addition, however, for the particular requirements of rig test analysis, the following new features have been developed and incorporate:- (a) It can carry out rig test analysis for a wide range of gas turbine engines if all the necessary test data are presented. (b) If the test data is incomplete, a computer simulation of the engine can be used to complete the analysis. (c) Performance deterioration of engine components can be detected by comparing the results of a test analysis and of a parallel simulation using stored characteristics of engine components in the “as new” condition. The program has been tested on simulated test data generated by engine models such as a turbojet and a turbofan. The results show it has close and repeatable agreement with design values. Further tests of the model have been carried out by applying it to the actual engine rig test data.


1992 ◽  
Author(s):  
KIRK D ◽  
ANDREW VAVRECK ◽  
ERIC LITTLE ◽  
LESLIE JOHNSON ◽  
BRETT SAYLOR

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Benny George ◽  
Nagalingam Muthuveerappan

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.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Benny George ◽  
Nagalingam Muthuveerappan

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.


Author(s):  
Walter Brockett ◽  
Angelo Koschier

The overall design of and Advanced Integrated Propulsion System (AIPS), powered by an LV100 gas turbine engine, is presented along with major test accomplishments. AIPS was a demonstrator program that included design, fabrication, and test of an advanced rear drive powerpack for application in a future heavy armored vehicle (54.4 tonnes gross weight). The AIPS design achieved significant improvements in volume, performance, fuel consumption, reliability/durability, weight and signature reduction. Major components of AIPS included the recuperated LV100 turbine engine, a hydrokinetic transmission, final drives, self-cleaning air filtration (SCAF), cooling system, signature reduction systems, electrical and hydraulic components, and control systems with diagnostics/prognostics and maintainability features.


Author(s):  
J. Pismenny ◽  
Y. Levy

The dependence of the vibration characteristics of gas turbine engines on the rotor speeds becomes highly complicated in engines with two and three rotors, both because of the simultaneous dynamic action of the multiple rotors and the ambiguous relationships between their speeds. In this paper, the gas turbine engine is analyzed in the context of the theory of non-linear oscillation — as a complex system comprising a large number of non-linear elements and multiple periodical forces of different frequencies (defined by the rotor speeds). This paper presents results, which indicate that the level of vibration can obtain critical values at certain relationships between the rotor speeds. As a practical application of this phenomena it is shown that the number of three-spool engines returns from the aircraft to the engine manufacturer, due to different kinds of malfunctions, for example due to activation of the “intensified vibration” alarm, may be approximately three times that of returns of analogous two-rotor engines.


2000 ◽  
Author(s):  
Zhiwu Xie ◽  
Ming Su ◽  
Shilie Weng

Abstract The static and transient performance of a gas turbine engine is determined by both the characteristics of the engine components and their interactions. This paper presents a generalized simulation framework that enables the integration of different component and system simulation codes. The concept of engine simulation integration and its implementation model is described. The model is designed as an object-oriented system, in which various simulation tasks are assigned to individual software components that interact with each other. A new design rationale called “message-based modeling” and its resulting class structure is presented and analyzed. The object model is implemented within a heterogeneous network environment. To demonstrate its flexibility, the codes that deal with different engine components are separately programmed on different computers running various operating systems. These components communicate with each other via a CORBA compliant ORB, which simulates the overall performance of an engine system. The resulting system has been tested on a Local Area Network (LAN) to simulate the transient response of a three-shaft gas turbine engine, subject to small fuel step perturbations. The simulation results for various network configurations are presented. It is evident that in contrast to a standalone computer simulation, the distributed implementation requires much longer simulation time. This difference of simulation efficiency is analyzed and explained. The limitations of this endeavor, along with some future research topics, are also reported in this paper.


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