The influence of design and performance parameters of an angular ball bearing on the stiffness of gas turbine engine rotor supports

There exist many approaches for gas turbine engine condition monitoring and fault diagnosis. Among them, gas path analysis depends on the relations between deviations of performance parameters and deviations of measurements, such as pressure, temperature, at some positions in the flow path. In the first author’s previous study, a dynamic tracking filter is combined with a nonlinear gas turbine model to form a fault diagnosis system. The dynamic tracking filter is composed with multiple negative feedback control loops in which the residuals between model outputs and measurements are driven to zero by adjusting the performance parameters. In the present study, an interaction analysis technique, named the Relative Gain Analysis (RGA), is introduced to design more convincing and formal tracking filter for a heavy-duty gas turbine diagnostic problem. The basic concept of the RGA method is introduced in this paper with a simple blending example. Then a gas turbine model built using the Simscape language and environment from the MathWorks Co. is presented. The effects of secondary air system on the performance of compressor and turbine are considered in this gas turbine model. The linear influence coefficient matrix for four performance parameters and four measurement parameters is obtained from the steady state simulation with proper disturbance of performance parameters. Then the relative gain matrix (RGM) is obtained from matrix operation. To evaluate the pairing rule proposed in the RGA method, four tracking loops are built up to form a tracking filter for the four performance parameters selected. Deviations of performance parameters are implanted into the gas turbine model by adjusting the scaling factors of performance maps; and then simulation results are taken as measurements needed for the tracking filter to run. Tracking results of performance parameters in different cases are given to show the tracking capability for isolated performance deviations and concurrent performance deviations.

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Effect of long service on the fine structure of the surface of gas turbine engine rotor blades

Strength of Materials ◽

10.1007/bf01528920 ◽

1977 ◽

Vol 9 (10) ◽

pp. 1257-1261

Author(s):

O. I. Marusii ◽

Yu. I. Koval' ◽

E. N. Kaspruk ◽

V. N. Torgov

Keyword(s):

Fine Structure ◽

Gas Turbine ◽

Gas Turbine Engine ◽

Rotor Blades ◽

Turbine Engine ◽

Engine Rotor

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Three-Dimensional Structural Evaluation of a Gas Turbine Engine Rotor

Volume 7A: Structures and Dynamics ◽

10.1115/gt2014-26375 ◽

2014 ◽

Author(s):

Partha S. Das

Keyword(s):

Finite Element ◽

Steady State ◽

Gas Turbine ◽

Gas Turbine Engine ◽

Complex Geometries ◽

Turbine Engine ◽

Industrial Gas Turbine ◽

Engine Rotor ◽

Engine Rotors ◽

Critical Locations

Engine rotors are one of the most critical components of a heavy duty industrial gas turbine engine, as it transfers mechanical energy from rotor blades to a generator for the production of electrical energy. In general, these are larger bolted rotors with complex geometries, which make analytical modeling of the rotor to determine its static, transient or dynamic behaviors difficult. For this purpose, powerful numerical analysis approaches, such as, the finite element method, in conjunction with high performance computers are being used to analyze the current rotor systems. The complexity in modeling bolted rotor behavior under various loadings, such as, airfoil, centrifugal and gravity loadings, including engine induced vibration is one of the main challenges of simulating the structural performance of an engine rotor. In addition, the internal structural temperature gradients that can be encountered in the transient state as a result of start-up and shutdown procedures are generally higher than those that occur in the steady-state and hence thermal shock is important factor to be considered relative to ordinary thermal stress. To address these issues, the current paper presents the steady-state & quasi-static analyses (to approximate transient responses) of two full 3-D industrial gas turbine engine rotors, SW501F & GE-7FA rotor, comprising of both compressor & turbine sections together. Full 3-D rotor analysis was carried out, since the 2-D axisymmetric model is inadequate to capture the complex geometries & out of plane behavior of the rotor. Both non-linear steady-state & transient analyses of a full gas turbine engine rotor was performed using the general purpose finite element analysis program ABAQUS. The paper presents in detail the FEA modeling technique, overall behavior of the full rotor under various loadings, as well as, the critical locations in the rotor with respect to its strength and life. The identification of these critical locations is needed to help with the repair of the existing rotors and to improve and extend the operational/service life of these rotors.

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Evaluation of a Gas-Lubricated Foil Bearing for Control of Gas Turbine Engine Rotor Critical Speeds

10.4271/751072 ◽

1975 ◽

Cited By ~ 3

Author(s):

R. H. Badgley ◽

J. Reddecliff

Keyword(s):

Gas Turbine ◽

Gas Turbine Engine ◽

Turbine Engine ◽

Critical Speeds ◽

Foil Bearing ◽

Engine Rotor

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Small Gas Turbine Engine Operating With High-Temperature Foil Bearings

Volume 5: Marine; Microturbines and Small Turbomachinery; Oil and Gas Applications; Structures and Dynamics, Parts A and B ◽

10.1115/gt2006-90791 ◽

2006 ◽

Cited By ~ 9

Author(s):

Hooshang Heshmat ◽

Michael J. Tomaszewski ◽

James F. Walton

Keyword(s):

High Temperature ◽

Gas Turbine ◽

Critical Speed ◽

Ball Bearing ◽

Gas Turbine Engine ◽

System Stability ◽

Exhaust Gas ◽

Turbine Engine ◽

Foil Bearing ◽

Bearing Life

A 134 Newton thrust class, 120,000 rpm turbojet was redesigned to incorporate a high-temperature compliant foil bearing aft of the turbine rotor and a compliantly mounted ball bearing forward of the centrifugal compressor–cold section. Two rotor-bearing system configurations were evaluated, one for operation above the bending critical speed and one for rigid rotor operation. Required characteristics for the foil bearing and ball bearing equipped with compliant foil damper mount were determined through a series of design tradeoff studies evaluating critical speeds and system stability. Following the design studies, the necessary hardware was fabricated, the engine assembled and operation to full speed achieved. Engine speed, rotor vibrations, compressor discharge pressure, exhaust gas temperature, thrust and fuel consumption were all recorded for both a baseline fluid lubricated ball bearing supported engine and the new turbojet engine using the hybrid foil bearing support system. Issues related to high-speed operation above the bending critical speed are identified and recommendations offered. Engine test data show that approximately 10% less fuel is consumed by the hybrid foil bearing mount system than the baseline conventional design. It is also shown that the foil bearing life was longer than the ball bearing life even though the foil bearing operated in the exhaust gas stream at temperatures exceeding 800°C. The results of this program demonstrate the feasibility of developing a completely oil-free foil bearing gas turbine engine.

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